Nortel Networks Switch 42C4911 User Manual

Alteon OSTM  
Application Guide  
Nortel 10Gb Ethernet Switch Module for IBM BladeCenter®  
Version 1.0  
Part Number: 42C4911, January 2007  
2350 Mission College Blvd.  
Suite 600  
Santa Clara, CA 95054  
www.bladenetwork.net  
 
Monitoring Ports 246  
Appendix B: RADIUS Server Configuration Notes 253  
Glossary 255  
Index 257  
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Figure 1-1:Switch management on the BladeCenter management module 26  
Figure 1-2:BOOTP Relay Agent Configuration 30  
Figure 1-3:DHCP Relay Agent Configuration 31  
Figure 2-1:Authenticating a Port Using EAPoL 69  
Figure 3-1:Default VLAN settings 81  
Figure 3-2:Port-based VLAN assignment 82  
Figure 3-3:802.1Q tagging (after port-based VLAN assignment) 82  
Figure 3-4:802.1Q tag assignment 83  
Figure 3-5:802.1Q tagging (after 802.1Q tag assignment) 83  
Figure 3-6:Example 1: Multiple VLANs with VLAN-Tagged Gigabit Adapters 85  
Figure 4-1:Port Trunk Group 94  
Figure 4-2:Port Trunk Group Configuration Example 97  
Figure 5-1:Using Multiple Instances of Spanning Tree Group 111  
Figure 5-2:Implementing Multiple Spanning Tree Groups 112  
Figure 7-1:QoS Model 124  
Figure 7-2:Layer 3 IPv4 packet 134  
Figure 7-3:Layer 2 802.1q/802.1p VLAN tagged packet 139  
Figure 8-1:The Router Legacy Network 145  
Figure 8-2:Switch-Based Routing Topology 146  
Figure 8-3:DHCP Relay Agent Configuration 154  
Figure 11-1:iBGP and eBGP 172  
Figure 11-2:Distributing Network Filters in Access Lists and Route Maps 175  
Figure 11-3:BGP Failover Configuration Example 182  
Figure 11-4:Route Aggregation and Default Route Redistribution 185  
Figure 12-1:OSPF Area Types 189  
Figure 12-2:OSPF Domain and an Autonomous System 190  
Figure 12-3:Injecting Default Routes 197  
Figure 12-4:OSPF Authentication 200  
Figure 12-5:A Simple OSPF Domain 205  
Figure 12-6:Configuring a Virtual Link 207  
Figure 12-7:Summarizing Routes 211  
Figure 13-1:Basic Layer 2 Failover 220  
Figure 13-2:Two trunks, each in a different Failover Trigger 221  
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Figure 13-3:Two trunks, one Failover Trigger 222  
Figure 13-4:A Non-VRRP, Hot-Standby Configuration 227  
Figure 13-5:Active-Active Redundancy 228  
Figure 13-6:Hot-Standby Redundancy 229  
Figure 13-7:Active-Active High-Availability Configuration 233  
Figure 13-8:Hot-Standby Configuration 239  
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Table 1-1:  
Table 1-2:  
Table 1-3:  
Table 1-4:  
Table 1-5:  
Table 4-1:  
Table 5-1:  
Table 7-1:  
Table 7-2:  
Table 7-3:  
Table 7-4:  
Table 7-5:  
Table 8-1:  
Table 8-2:  
Table 8-3:  
GbESM IP addresses, based on switch-module bay numbers 24  
User Access Levels 47  
Alteon OS-proprietary Attributes for RADIUS 47  
Default TACACS+ Authorization Levels 49  
Alternate TACACS+ Authorization Levels 49  
Actor vs. Partner LACP configuration 101  
Ports, Trunk Groups, and VLANs 106  
Well-Known Protocol Types 126  
Well-Known Application Ports 127  
Well-Known TCP flag values 127  
ACL Precedence Groups 128  
Default QoS Service Levels 136  
Subnet Routing Example: IP Address Assignments 148  
Subnet Routing Example: IP Interface Assignments 148  
Subnet Routing Example: Optional VLAN Ports 150  
Table 13-1: VRRP Tracking Parameters 230  
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Preface  
The Alteon OS Application Guide describes how to configure and use the Alteon OS software  
on the 10Gb Ethernet Switch Module for IBM BladeCenter. For documentation on installing  
the switch physically, see the Installation Guide for your GbE Switch Module (GbESM).  
Who Should Use This Guide  
This Application Guide is intended for network installers and system administrators engaged in  
configuring and maintaining a network. The administrator should be familiar with Ethernet  
concepts, IP addressing, Spanning Tree Protocol, and SNMP configuration parameters.  
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What You’ll Find in This Guide  
This guide will help you plan, implement, and administer Alteon OS software. Where possible,  
each section provides feature overviews, usage examples, and configuration instructions.  
Chapter 1, “Accessing the Switch,” describes how to access the GbE Switch Module to  
configure, view information and run statistics on the switch. This chapter also discusses  
different methods to manage the switch for remote administrators using specific IP  
addresses, authentication, Secure Shell (SSH), and Secure Copy (SCP).  
Chapter 2, “Port-based Network Access Control,” describes how to authenticate devices  
attached to a LAN port that has point-to-point connection characteristics. It prevents  
access to ports that fail authentication and authorization. This feature provides security to  
ports of the GbESM that connect to blade servers.  
Chapter 3, “VLANs,” describes how to configure Virtual Local Area Networks (VLANs)  
for creating separate network segments, including how to use VLAN tagging for devices  
that use multiple VLANs. This chapter also describes Protocol-based VLANs, Private  
VLANs, and Generic VLAN Registration Protocol (GVRP).  
Chapter 4, “Ports and Trunking,” describes how to group multiple physical ports together  
to aggregate the bandwidth between large-scale network devices.  
Chapter 5, “Spanning Tree Group,” discusses how Spanning Trees configure the network  
so that the switch uses the most efficient path when multiple paths exist.  
Chapter 6, “Rapid Spanning Tree Protocol/Multiple Spanning Tree Protocol,” describes  
Rapid Spanning Tree and Multiple Spanning Tree configurations.  
Chapter 7, “Quality of Service,” discusses Quality of Service features, including IP filter-  
ing using Access Control Lists, Differentiated Services, and IEEE 802.1p priority values.  
Part 2: IP Routing  
Chapter 8, “Basic IP Routing,” describes how to configure the GbE Switch Module for IP  
routing using IP subnets, and DHCP Relay.  
Chapter 9, “Routing Information Protocol,” describes how the Alteon OS software imple-  
ments standard RIP for exchanging TCP/IP route information with other routers.  
Chapter 10, “IGMP,” describes how the Alteon OS software implements IGMP Snooping  
or IGMP Relay to handle multicast traffic efficiently.  
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ported in Alteon OS.  
Chapter 12, “OSPF,” describes OSPF concepts, how OSPF is implemented in Alteon OS,  
and examples of how to configure your switch for OSPF support.  
Part 3: High Availability Fundamentals  
Chapter 13, “High Availability,” describes how to use the Virtual Router Redundancy Pro-  
tocol (VRRP) to ensure that network resources remain available if one GbE Switch Mod-  
ule is removed for service.  
Part 4: Appendices  
Appendix A, “Troubleshooting,” discusses two tools for troubleshooting your switch—  
monitoring ports and filtering session dumps.  
Appendix B, “RADIUS Server Configuration Notes,” discusses how to modify RADIUS  
configuration files for the Nortel Networks BaySecure Access Control RADIUS server, to  
provide authentication for users of the GbE Switch Module.  
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Typographic Conventions  
The following table describes the typographic styles used in this book.  
Table 1 Typographic Conventions  
Typeface or  
Symbol  
Meaning  
Example  
AaBbCc123  
This type is used for names of commands,  
files, and directories used within the text.  
View the readme.txtfile.  
It also depicts on-screen computer output and Main#  
prompts.  
AaBbCc123  
This bold type appears in command exam-  
ples. It shows text that must be typed in  
exactly as shown.  
Main# sys  
<AaBbCc123> This italicized type appears in command  
To establish a Telnet session, enter:  
examples as a parameter placeholder. Replace host# telnet <IP address>  
the indicated text with the appropriate real  
name or value when using the command. Do  
not type the brackets.  
This also shows book titles, special terms, or Read your Users Guide thoroughly.  
words to be emphasized.  
[ ]  
Command items shown inside brackets are host# ls [-a]  
optional and can be used or excluded as the  
situation demands. Do not type the brackets.  
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How to Get Help  
If you need help, service, or technical assistance, see the "Getting help and  
technical assistance" appendix in the Nortel 10Gb Ethernet Switch Module for  
IBM BladeCenter Installation Guide.  
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Part 1: Basic Switching  
This section discusses basic switching functions. This includes how to access and manage the  
switch:  
Accessing the switch  
Port-Based Network Access Control  
VLANs  
Port Trunking  
Spanning Tree Protocol  
Rapid Spanning Tree and Protocol and Multiple Spanning Tree Protocol  
Quality of Service  
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CHAPTER 1  
Accessing the Switch  
and statistics about the GbE Switch Module. This chapter discusses different methods of  
accessing the switch and ways to secure the switch for remote administrators:  
“RADIUS Authentication and Authorization” on page 44  
“TACACS+ Authentication” on page 48  
“LDAP Authentication and Authorization” on page 53  
“Secure Shell and Secure Copy” on page 55  
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Management module setup  
The BladeCenter GbE Switch Module is an integral subsystem within the overall BladeCenter  
system. The BladeCenter chassis includes a management module as the central element for  
overall chassis management and control.  
You can use the management module to configure and manage the GbE Switch Module. The  
GbE Switch Module communicates with the management module(s) through its internal port  
15 (MGT1) and port 16 (MGT2), which you can access through the 100 Mbps Ethernet port on  
each management module. The factory default settings permit management and control access  
to the switch module only through the management module, or the built-in serial port. You can  
use the external Ethernet ports (EXT1-EXT7) on the switch module for management and con-  
trol of the switch, by selecting this mode as an option through the management module config-  
uration utility program (see the applicable BladeCenter Installation and Users Guide  
publications for more information).  
NOTE Support for each management module is provided by a separate management port  
(MGT1 and MGT2). One port is active, and the other port is used as a backup.  
Factory-Default vs. MM assigned IP Addresses  
Each GbE Switch Module must be assigned its own Internet Protocol address, which is used  
for communication with an SNMP network manager or other transmission control protocol/  
Internet Protocol (TCP/IP) applications (for example, BootP or TFTP). The factory-default IP  
address is 10.90.90.8x, where x corresponds to the number of the bay into which the GbE  
Switch Module is installed. For additional information, see the Installation Guide. The man-  
agement module assigns an IP address of 192.168.70.1xx, where xx corresponds to the number  
of the bay into which each GbE Switch Module is installed, as shown in the following table:  
Table 1-1 GbESM IP addresses, based on switch-module bay numbers  
Bay number  
Bay 7  
Factory-default IP address  
10.90.90.80  
IP address assigned by MM  
192.168.70.133  
Bay 8  
10.90.90.82  
192.168.70.134  
Bay 9  
10.90.90.81  
192.168.70.135  
Bay 10  
10.90.90.83  
192.168.70.136  
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NOTE Before you install the GbESM in Bay 8 or Bay 10, confirm that your blade  
I/O Expansion adapter supports communication to these I/O bays.  
Default Gateway  
The default Gateway IP address determines where packets with a destination address outside  
the current subnet should be sent. Usually, the default Gateway is a router or host acting as an  
IP gateway to handle connections to other subnets of other TCP/IP networks. If you want to  
access the GbE Switch Module from outside your local network, use the management module  
to assign a default Gateway address to the GbE Switch Module. Choose I/O Module Tasks >  
Configuration from the navigation pane on the left, and enter the default Gateway IP address  
(for example, 192.168.70.125). Click Save.  
Configuring management module for switch access  
Complete the following initial configuration steps:  
1. Connect the Ethernet port of the management module to a 10/100 Mbps network (with  
access to a management station) or directly to a management station.  
2. Access and log on to the management module, as described in the BladeCenter Manage-  
ment Module User’s Guide. The management module provides the appropriate IP  
addresses for network access (see the applicable BladeCenter Installation and User’s  
Guide publications for more information).  
3. Select Configuration on the I/O Module Tasks menu on the left side of the BladeCenter  
Management Module window. See Figure 1-1.  
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Figure 1-1 Switch management on the BladeCenter management module  
4. You can use the default IP addresses provided by the management module, or you can  
assign a new IP address to the switch module through the management module. You can  
assign this IP address through one of the following methods:  
Manually through the BladeCenter management module  
Automatically through the IBM Director Configuration Wizard (available in  
Director release 5.20.1)  
NOTE If you change the IP address of the GbE Switch Module, make sure that the switch  
module and the management module both reside on the same subnet.  
5. Enable the following features in the management module:  
External Ports (I/O Module Tasks > Admin/Power/Restart > Advanced Setup)  
External management over all ports (Configuration > Advanced Configuration)  
This setting is required if you want to access the management network through the  
external data ports (EXT1 - EXT6) and the external management port (EXT7) on the  
GbE Switch Module.  
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The default value is Disabledfor both features. If these features are not already enabled,  
change the value to Enabled, then Save.  
NOTE In Advanced Configuration > Advanced Setup, enable “Preserve new IP configura-  
tion on all switch resets,” to retain the switch’s IP interface when you restore factory defaults.  
This setting preserves the management port’s IP address in the management module’s memory,  
so you maintain connectivity to the management module after a reset.  
You can now start a Telnet session, Browser-Based Interface (Web) session, a Secure Shell ses-  
sion, or a secure HTTPS session to the GbE Switch Module.  
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External management port setup  
In addition to the internal management ports (MGT1 and MGT2), the 10Gb Ethernet  
Switch Module (GbESM) also has an external management port (EXT7) to support  
out-of-band management traffic. Port EXT7 allows you to perform data transfers without  
taxing the data ports (EXT1-EXT6). Some commands (for example, software image transfers  
such as /boot/gtimg) that initiate data transfers provide an option for choosing the port  
over which to perform the transfer.  
To use the external management port, you must configure the external management interface  
and gateway, as shown in the following configuration example.  
Configuring the external management interface  
Complete the following steps to configure port EXT7 for external management:  
1. Use Telnet to access the switch CLI, and configure the external management interface:  
>> # /cfg/l3/if 249  
(Select IP interface 249)  
>> IP Interface 249# addr 100.20.10.3  
>> IP Interface 249# ena  
>> IP Interface 249# ..  
>> Layer 3# gw 253  
(Assign IP address for the interface)  
(Enable the interface)  
(Select gateway 253)  
>> Default gateway 253# addr 100.20.10.5 (Assign IP address for the gateway)  
>> Default gateway 253# ena  
>> Default gateway 253# apply  
>> Default gateway 253# save  
(Enable the gateway)  
(Make the configuration active)  
(Save your changes)  
Interface 249 and gateway 253 are used for switch management through port EXT7.  
2. Enable port EXT7.  
>> # /cfg/port ext7/ena  
>> Port EXT7# apply  
>> Port EXT7# save  
(Enable port EXT7)  
(Make the configuration active)  
(Save your changes)  
By default, port EXT7 is a member of management VLAN 4094.  
Once the external management network is configured, you can start a Telnet session,  
Browser-Based Interface (Web) session, a Secure Shell session, or a secure HTTPS session to  
the GbESM. To access the GbESM through the external management port, use the IP address  
for IP interface 249.  
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Using Telnet  
Use the management module to access the GbE Switch Module through Telnet. Choose  
I/O Module Tasks > Configuration from the navigation pane on the left. Select a bay number  
and click Advanced Configuration > Start Telnet/Web Session > Start Telnet Session. A  
Telnet window opens a connection to the Switch Module (requires Java 1.4 Plug-in).  
Once you have configured the GbE Switch Module with an IP address and gateway, you can  
access the switch from any workstation connected to the management network. Telnet access  
provides the same options for user and administrator access as those available through the  
management module, minus certain telnet and management commands.  
To establish a Telnet connection with the switch, you can run the Telnet program on your  
workstation and issue the Telnet command, followed by the switch IP address:  
telnet <switch IP address> [-m|-mgt|-e|-ext7|-d|-data]  
By default, the -m or -mgtoption for management ports is used. To use the internal  
management port, specify the -mor -mgtoption. To use the external management port,  
specify the -e or -ext7 option.  
Connect to the Switch via SSH  
The SSH (Secure Shell) protocol enables you to securely log into another computer over a net-  
work to execute commands remotely. As a secure alternative to using Telnet to manage switch  
configuration, SSH ensures that all data sent over the network is encrypted and secure. For  
more information, see “Secure Shell and Secure Copy” on page 55. For more information on  
the CLI, see the Alteon OS Command Reference.  
BOOTP Relay Agent  
The GbE Switch Module can function as a Bootstrap Protocol relay agent, enabling the switch  
to forward a client request for an IP address up to two BOOTP servers with IP addresses that  
have been configured on the switch.  
When a switch receives a BOOTP request from a BOOTP client requesting an IP address, the  
switch acts as a proxy for the client. The request is then forwarded as a UDP Unicast MAC  
layer message to two BOOTP servers whose IP addresses are configured on the switch. The  
servers respond to the switch with a Unicast reply that contains the default gateway and IP  
address for the client. The switch then forwards this reply back to the client.  
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Figure 1-2 shows a basic BOOTP network example.  
Boston  
Raleigh  
BladeCenter  
BladeCenter  
20.1.1.1  
10.1.1.2  
enter  
BladeCenter acts as  
BOOTP Relay Agent  
BOOT Client  
asks for IP from  
BOOTP server  
BOOTP Server  
Figure 1-2 BOOTP Relay Agent Configuration  
The use of two servers provide failover redundancy. The client request is forwarded to both  
BOOTP servers configured on the switch. However, no health checking is supported.  
Configuring the BOOTP Relay Agent  
To enable the GbE Switch Module to be the BOOTP forwarder, you need to configure the  
BOOTP server IP addresses on the switch, and enable BOOTP relay on the interface(s) on  
which the BOOTP requests are received.  
Generally, you should configure the command on the switch IP interface that is closest to the  
client, so that the BOOTP server knows from which IP subnet the newly allocated IP address  
should come.  
Use the following commands to configure the switch as a BOOTP relay agent:  
>> # /cfg/l3/bootp  
>> Bootstrap Protocol Relay# addr <IP address>(IP address of BOOTP server)  
>> Bootstrap Protocol Relay# addr2 <IP address>(IP address of 2nd BOOTP server)  
>> Bootstrap Protocol Relay# on  
>> Bootstrap Protocol Relay# off  
>> Bootstrap Protocol Relay# cur  
(Globally turn BOOTP relay on)  
(Globally turn BOOTP relay off)  
(Display current configuration)  
Use the following command to enable the Relay functionality on an IP interface:  
>> # /cfg/l3/if <interface number>/relay ena  
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DHCP Relay Agent  
DHCP is described in RFC 2131, and the DHCP relay agent supported on the GbESM is  
described in RFC 1542. DHCP uses UDP as its transport protocol. The client sends messages  
to the server on port 67 and the server sends messages to the client on port 68.  
DHCP defines the methods through which clients can be assigned an IP address for a finite  
lease period and allowing reassignment of the IP address to another client later. Additionally,  
DHCP provides the mechanism for a client to gather other IP configuration parameters it needs  
to operate in the TCP/IP network.  
In the DHCP environment, the switch acts as a relay agent. The DHCP relay feature  
(/cfg/l3/bootp) enables the switch to forward a client request for an IP address to two  
BOOTP servers with IP addresses that have been configured on the switch.  
When a switch receives a UDP broadcast on port 67 from a DHCP client requesting an IP  
address, the switch acts as a proxy for the client, replacing the client source IP (SIP) and desti-  
nation IP (DIP) addresses. The request is then forwarded as a UDP Unicast MAC layer mes-  
sage to two BOOTP servers whose IP addresses are configured on the switch. The servers  
respond as a a UDP Unicast message back to the switch, with the default gateway and IP  
address for the client. The destination IP address in the server response represents the interface  
address on the switch that received the client request. This interface address tells the switch on  
which VLAN to send the server response to the client.  
DHCP Relay Agent Configuration  
To enable the GbESM to be the BOOTP forwarder, you need to configure the DHCP/BOOTP  
server IP addresses on the switch. Generally, you should configure the command on the switch  
IP interface closest to the client so that the DHCP server knows from which IP subnet the  
newly allocated IP address should come.  
The following figure shows a basic DHCP network example:  
GbESM  
DHCP  
Server  
BladeCenter  
Figure 1-3 DHCP Relay Agent Configuration  
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In GbESM implementation, there is no need for primary or secondary servers. The client  
request is forwarded to the BOOTP servers configured on the switch. The use of two servers  
provide failover redundancy. However, no health checking is supported.  
Use the following commands to configure the switch as a DHCP relay agent:  
>> # /cfg/l3/bootp  
>> Bootstrap Protocol Relay# addr  
>> Bootstrap Protocol Relay# addr2  
>> Bootstrap Protocol Relay# on  
>> Bootstrap Protocol Relay# off  
>> Bootstrap Protocol Relay# cur  
(Set IP address of BOOTP server)  
(Set IP address of 2nd BOOTP server)  
(Globally turn BOOTP relay on)  
(Globally turn BOOTP relay off)  
(Display current configuration)  
Additionally, DHCP Relay functionality can be assigned on a per interface basis. Use the fol-  
lowing command to enable the Relay functionality:  
>> # /cfg/l3/if <interface number>/relay ena  
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Using the Browser-Based Interface  
Use the management module to access the GbE Switch Module through a Web session. Choose  
I/O Module Tasks > Configuration from the navigation pane on the left. Select a bay number  
and click Advanced Configuration > Start Telnet/Web Session > Start Web Session. A  
browser window opens a connection to the Switch Module.  
The Browser-based Interface (BBI) provides access to the common configuration, manage-  
ment and operation features of the GbE Switch Module through your Web browser. For more  
information, refer to the BBI Quick Guide.  
By default, BBI access is enabled on the switch (/cfg/sys/access/http ena).  
Configuring BBI Access via HTTP  
To enable BBI access on the switch via HTTP, use the following command:  
/cfg/sys/access/http ena  
The management module requires the default HTTP web server port (port 80) to access the  
BBI. However, you can change the default Web server port with the following command:  
/cfg/sys/access/wport<x>  
For workstation access to your switch via the Browser-Based Interface, open a Web browser  
window and type in the URL using the IP interface address of the switch, such as http://  
10.10.10.1.  
Configuring BBI Access via HTTPS  
The BBI can also be accessed via a secure HTTPS connection over management and data  
ports.  
To enable BBI Access on the switch via HTTPS, use the following command:  
/cfg/sys/access/https/access ena  
To change the HTTPS Web server port number from the default port 443, use the following  
command:  
/cfg/sys/access/https/port <x>  
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Accessing the BBI via HTTPS requires that you generate a certificate to be used during the key  
exchange. A default certificate is created the first time HTTPS is enabled, but you can create a  
new certificate defining the information you want to be used in the various fields.  
>> /cfg/sys/access/https/generate  
Country Name (2 letter code) [ ]: <country code>  
State or Province Name (full name) []: <state>  
Locality Name (eg, city) []: <city>  
Organization Name (eg, company) []: <company>  
Organizational Unit Name (eg, section) []: <org. unit>  
Common Name (eg, YOUR name) []: <name>  
Email (eg, email address) []: <email address>  
Confirm generating certificate? [y/n]: y  
Generating certificate. Please wait (approx 30 seconds)  
restarting SSL agent  
The certificate can be saved to flash for use if the switch is rebooted by using the apply and  
save commands.  
When a client (e.g. web browser) connects to the switch, they will be asked if they accept the  
certificate and can verify that the fields are what expected. Once BBI access is granted to the  
client, the BBI can be used as described in the BBI Quick Guide.  
The BBI is organized at a high level as follows:  
Context buttons – allow you to select the type of action you wish to perform. The Configura-  
tion button provides access to the configuration elements for the entire switch. The Statistics  
button provides access to the switch statistics and state information. The Dashboard button  
allows you to display settings and operating status of a variety of switch features.  
Navigation Window – provides a menu list of switch features and functions, as follows:  
System – this folder provides access to the configuration elements for the entire switch.  
General  
User Table  
Radius  
TACACS+  
LDAP  
NTP  
Boot  
Syslog/Trap Features  
Config/Image Control  
Mgmt  
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Switch Ports – configure each of the physical ports on the switch.  
Port-Based Port Mirroring – configure port mirroring and mirror port.  
Layer 2 – Configure Quality of Service (QoS) features for the switch.  
802.1x  
FDB  
Virtual LANs  
Spanning Tree Groups  
MSTP/RSTP  
Failover  
Trunk Groups  
Trunk Hash  
LACP  
Uplink Fast  
Layer 3 – Configure Layer 3 features for the switch.  
IP Interfaces  
Network Routes  
Static IPMC Routes  
ARP  
Network Filters  
Route Maps  
Border Gateway Protocol  
Default Gateways  
IGMP  
OSPF Routing Protocol  
Routing Information Protocol  
Virtual Router Redundancy Protocol  
Domain Name System  
Bootstrap Protocol Relay  
General  
QoS – Configure Quality of Service (QoS) features for the switch.  
802.1p  
DSCP  
Access Control – Configure Access Control Lists to filter IP packets.  
Access Control Lists  
Access Control List Groups  
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Using SNMP  
Alteon OS provides SNMP v1.0 and SNMP v3.0 support for access through any network man-  
agement software, such as IBM Director or HP-OpenView.  
SNMP v1.0  
To access the SNMP agent on the GbESM, the read and write community strings on the SNMP  
manager should be configured to match those on the switch. The default read community  
string on the switch is publicand the default write community string is private.  
The read and write community strings on the switch can be changed using the following com-  
mands on the CLI:  
>> /cfg/sys/ssnmp/rcomm  
and  
>> /cfg/sys/ssnmp/wcomm  
The SNMP manager should be able to reach the management interface or any one of the IP  
interfaces on the switch.  
For the SNMP manager to receive the traps sent out by the SNMP agent on the switch  
(SNMPv1 only), configure the trap host on the switch with the following command:  
/cfg/sys/ssnmp/trsrc <1-250>  
SNMP v3.0  
SNMPv3 is an enhanced version of the Simple Network Management Protocol, approved by  
the Internet Engineering Steering Group in March, 2002. SNMP v3.0 contains additional secu-  
rity and authentication features that provide data origin authentication, data integrity checks,  
timeliness indicators and encryption to protect against threats such as masquerade, modifica-  
tion of information, message stream modification and disclosure.  
SNMPv3 ensures that the client can use SNMPv3 to query the MIBs, mainly for security.  
To access the SNMP v3.0 menu, enter the following command in the CLI:  
>> # /cfg/sys/ssnmp/snmpv3  
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For more information on SNMP MIBs and the commands used to configure SNMP on the  
switch, see the Alteon OS Command Reference.  
Default configuration  
Alteon OS has two SNMP v3 users by default. Both of the following users have access to all  
the MIBs supported by the switch:  
1) username 1: adminmd5/password adminmd5. Authentication used is MD5.  
2) username 2: adminsha/password adminsha. Authentication used is SHA.  
To configure an SNMP user name, enter the following command from the CLI:  
>> # /cfg/sys/ssnmp/snmpv3/usm 1  
User Configuration:  
Users can be configured to use the authentication/privacy options. The GbESM support two  
authentication algorithms: MD5 and SHA, as specified in the following command:  
/c/sys/ssnmp/snmpv3/usm <x>/auth md5|sha  
1. To configure a user with name 'admin,' authentication type MD5, and authentication  
password of 'admin,' privacy option DES with privacy password of 'admin,' use the fol-  
lowing CLI commands.  
>> # /cfg/sys/ssnmp/snmpv3/usm 5  
>> SNMPv3 usmUser 5# name "admin"  
>> SNMPv3 usmUser 5# auth md5  
>> SNMPv3 usmUser 5# authpw admin  
>> SNMPv3 usmUser 5# priv des  
>> SNMPv3 usmUser 5# privpw admin  
(Configure ‘admin’ user type)  
2. Configure a user access group, along with the views the group may access. Use the access  
table to configure the group’s access level.  
>> # /cfg/sys/ssnmp/snmpv3/access 5  
>> SNMPv3 vacmAccess 5# name "admingrp"  
>> SNMPv3 vacmAccess 5# level authPriv  
>> SNMPv3 vacmAccess 5# rview "iso"  
>> SNMPv3 vacmAccess 5# wview "iso"  
>> SNMPv3 vacmAccess 5# nview "iso"  
(Configure an access group)  
Because the read view (rview), write view (wview), and notify view (nview) are all set to  
“iso,” the user type has access to all private and public MIBs.  
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3. Assign the user to the user group. Use the group table to link the user to a particular  
access group.  
>> # /cfg/sys/ssnmp/snmpv3/group 5  
>> SNMPv3 vacmSecurityToGroup 5# uname admin  
>> SNMPv3 vacmSecurityToGroup 5# gname admingrp  
If you want to allow user access only to certain MIBs, see the 'View based Configuration' sec-  
tion.  
View based Configurations  
CLI User equivalent  
To configure an SNMP user equivalent to the CLI 'user,' use the following configuration:  
/c/sys/ssnmp/snmpv3/usm 4  
name "usr"  
/c/sys/ssnmp/snmpv3/access 3  
name "usrgrp"  
(Configure the user)  
(Configure access group 3)  
rview "usr"  
wview "usr"  
nview "usr"  
/c/sys/ssnmp/snmpv3/group 4  
uname usr  
(Assign user to access group 3)  
gname usrgrp  
/c/sys/ssnmp/snmpv3/view 6  
name "usr"  
tree "1.3.6.1.4.1.1872.2.5.1.2"  
/c/sys/ssnmp/snmpv3/view 7  
name "usr"  
(Create views for user)  
(Agent statistics)  
tree "1.3.6.1.4.1.1872.2.5.1.3"  
/c/sys/ssnmp/snmpv3/view 8  
name "usr"  
tree "1.3.6.1.4.1.1872.2.5.2.2"  
/c/sys/ssnmp/snmpv3/view 9  
name "usr"  
(Agent information)  
(L2 statistics)  
tree "1.3.6.1.4.1.1872.2.5.2.3"  
/c/sys/ssnmp/snmpv3/view 10  
name "usr"  
tree "1.3.6.1.4.1.1872.2.5.3.2"  
/c/sys/ssnmp/snmpv3/view 11  
name "usr"  
(L2 information)  
(L3 statistics)  
tree "1.3.6.1.4.1.1872.2.5.3.3"  
(L3 information)  
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CLI oper equivalent  
/c/sys/ssnmp/snmpv3/usm 5  
name "oper"  
(Configure the oper)  
/c/sys/ssnmp/snmpv3/access 4  
name "opergrp"  
(Configure access group 4)  
rview "oper"  
wview "oper"  
nview "oper"  
/c/sys/ssnmp/snmpv3/group 4  
uname oper  
(Assign oper to access group 4)  
gname opergrp  
/c/sys/ssnmp/snmpv3/view 20  
name "usr"  
tree "1.3.6.1.4.1.1872.2.5.1.2"  
/c/sys/ssnmp/snmpv3/view 21  
name "usr"  
(Create views for oper)  
(Agent statistics)  
tree "1.3.6.1.4.1.1872.2.5.1.3"  
/c/sys/ssnmp/snmpv3/view 22  
name "usr"  
tree "1.3.6.1.4.1.1872.2.5.2.2"  
/c/sys/ssnmp/snmpv3/view 23  
name "usr"  
(Agent information)  
(L2 statistics)  
tree "1.3.6.1.4.1.1872.2.5.2.3"  
/c/sys/ssnmp/snmpv3/view 24  
name "usr"  
tree "1.3.6.1.4.1.1872.2.5.3.2"  
/c/sys/ssnmp/snmpv3/view 25  
name "usr"  
(L2 information)  
(L3 statistics)  
tree "1.3.6.1.4.1.1872.2.5.3.3"  
(L3 information)  
Configuring SNMP Trap Hosts  
SNMPv1 trap host  
1. Configure a user with no authentication and password.  
/c/sys/ssnmp/snmpv3/usm 10  
name "v1trap"  
(Configure user named “v1trap”)  
2. Configure an access group and group table entries for the user. Use the following com-  
mand to specify which traps can be received by the user  
/c/sys/ssnmp/snmpv3/access <x>/nview  
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In the example below the user will receive the traps sent by the switch.  
/c/sys/ssnmp/snmpv3/access 10  
name "v1trap"  
(Define access group to view SNMPv1 traps)  
model snmpv1  
nview "iso"  
/c/sys/ssnmp/snmpv3/group 10  
model snmpv1  
(Assign user to the access group)  
uname v1trap  
gname v1trap  
3. Configure an entry in the notify table.  
/c/sys/ssnmp/snmpv3/notify 10  
name v1trap  
(Assign user to the notify table)  
tag v1trap  
4. Specify the IP address and other trap parameters in the targetAddr and targetParam  
tables. Use the following command to specify the user name used with this targetParam  
table:  
c/sys/ssnmp/snmpv3/tparam <x>/uname  
/c/sys/ssnmp/snmpv3/taddr 10  
name v1trap  
(Define an IP address to send traps)  
addr 47.80.23.245  
taglist v1trap  
pname v1param  
/c/sys/ssnmp/snmpv3/tparam 10  
name v1param  
(Specify SNMPv1 traps to send)  
mpmodel snmpv1  
uname v1trap  
model snmpv1  
5. Use the community table to specify which community string is used in the trap.  
/c/sys/ssnmp/snmpv3/comm 10  
index v1trap  
(Define the community string)  
name public  
uname v1trap  
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SNMPv2 trap host configuration  
The SNMPv2 trap host configuration is similar to the SNMPv1 trap host configuration.  
Wherever you specify the model, use snmpv2instead of snmpv1.  
c/sys/ssnmp/snmpv3/usm 10  
name "v2trap"  
(Configure user named “v2trap”)  
/c/sys/ssnmp/snmpv3/access 10  
name "v2trap"  
(Define access group to view SNMPv2 traps)  
model snmpv2  
nview "iso"  
/c/sys/ssnmp/snmpv3/group 10  
model snmpv2  
(Assign user to the access group)  
uname v2trap  
gname v2trap  
/c/sys/ssnmp/snmpv3/notify 10  
name v2trap  
(Assign user to the notify table)  
tag v2trap  
/c/sys/ssnmp/snmpv3/taddr 10  
name v2trap  
(Define an IP address to send traps)  
addr 47.81.25.66  
taglist v2trap  
pname v2param  
/c/sys/ssnmp/snmpv3/tparam 10  
name v2param  
(Specify SNMPv2 traps to send)  
(Define the community string)  
mpmodel snmpv2c  
uname v2trap  
model snmpv2  
/c/sys/ssnmp/snmpv3/comm 10  
index v2trap  
name public  
uname v2trap  
SNMPv3 trap host configuration  
To configure a user for SNMPv3 traps, you can choose to send the traps with both privacy and  
authentication, with authentication only, or without privacy or authentication.  
This is configured in the access table using the following commands:  
/c/sys/ssnmp/snmpv3/access <x>/level  
/c/sys/ssnmp/snmpv3/tparam <x>  
Configure the user in the user table accordingly.  
It is not necessary to configure the community table for SNMPv3 traps because the community  
string is not used by SNMPv3.  
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The following example shows how to configure a SNMPv3 user v3trapwith authentication  
only:  
/c/sys/ssnmp/snmpv3/usm 11  
(Configure user named “v3trap”)  
name "v3trap"  
auth md5  
authpw v3trap  
/c/sys/ssnmp/snmpv3/access 11  
name "v3trap"  
(Define access group to view SNMPv3 traps)  
level authNoPriv  
nview "iso"  
/c/sys/ssnmp/snmpv3/group 11  
uname v3trap  
gname v3trap  
/c/sys/ssnmp/snmpv3/notify 11  
name v3trap  
tag v3trap  
/c/sys/ssnmp/snmpv3/taddr 11  
name v3trap  
(Assign user to the access group)  
(Assign user to the notify table)  
(Define an IP address to send traps)  
addr 47.81.25.66  
taglist v3trap  
pname v3param  
/c/sys/ssnmp/snmpv3/tparam 11  
name v3param  
(Specify SNMPv3 traps to send)  
(Set the authentication level)  
uname v3trap  
level authNoPriv  
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Securing Access to the Switch  
Secure switch management is needed for environments that perform significant management  
functions across the Internet. The following are some of the functions for secured manage-  
ment:  
Authentication and authorization of remote administrators: see “RADIUS Authentication  
Encryption of management information exchanged between the remote administrator and  
the switch: see “Secure Shell and Secure Copy” on page 55  
The following sections are addressed in this section:  
“TACACS+ Authentication” on page 48  
“LDAP Authentication and Authorization” on page 53  
“Secure Shell and Secure Copy” on page 55  
“End User Access Control” on page 61  
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RADIUS Authentication and Authorization  
Alteon OS supports the RADIUS (Remote Authentication Dial-in User Service) method to  
authenticate and authorize remote administrators for managing the switch. This method is  
based on a client/server model. The Remote Access Server (RAS)—the switch—is a client to  
the back-end database server. A remote user (the remote administrator) interacts only with the  
RAS, not the back-end server and database.  
RADIUS authentication consists of the following components:  
A protocol with a frame format that utilizes UDP over IP (based on RFC 2138 and 2866)  
A centralized server that stores all the user authorization information  
A client, in this case, the switch  
The GbE Switch Module—acting as the RADIUS client—communicates to the RADIUS  
server to authenticate and authorize a remote administrator using the protocol definitions spec-  
ified in RFC 2138 and 2866. Transactions between the client and the RADIUS server are  
authenticated using a shared key that is not sent over the network. In addition, the remote  
administrator passwords are sent encrypted between the RADIUS client (the switch) and the  
back-end RADIUS server.  
How RADIUS Authentication Works  
1. Remote administrator connects to the switch and provides user name and password.  
2. Using Authentication/Authorization protocol, the switch sends request to authentication  
server.  
3. Authentication server checks the request against the user ID database.  
administrative access.  
Configuring RADIUS on the Switch  
Use the following procedure to configure Radius authentication on your GbE Switch Module.  
For more information, see Appendix B, “RADIUS Server Configuration Notes.”  
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1. Turn RADIUS authentication on, then configure the Primary and Secondary RADIUS  
servers.  
>> Main# /cfg/sys/radius  
>> RADIUS Server# on  
Current status: OFF  
(Select the RADIUS Server menu)  
(Turn RADIUS on)  
New status:  
ON  
>> RADIUS Server# prisrv 10.10.1.1  
(Enter primary server IP)  
Current primary RADIUS server:  
0.0.0.0  
New pending primary RADIUS server: 10.10.1.1  
>> RADIUS Server# secsrv 10.10.1.2  
Current secondary RADIUS server:  
(Enter secondary server IP)  
0.0.0.0  
New pending secondary RADIUS server: 10.10.1.2  
2. Configure the RADIUS secret.  
>> RADIUS Server# secret  
Enter new RADIUS secret: <1-32 character secret>  
CAUTIONIf you configure the RADIUS secret using any method other than through the con-  
sole port or management module, the secret may be transmitted over the network as clear text.  
!
3. If desired, you may change the default UDP port number used to listen to RADIUS.  
The well-known port for RADIUS is 1645.  
>> RADIUS Server# port  
Current RADIUS port: 1645  
Enter new RADIUS port [1500-3000]: <UDP port number>  
4. Configure the number retry attempts for contacting the RADIUS server, and the timeout  
period.  
>> RADIUS Server# retries  
Current RADIUS server retries: 3  
Enter new RADIUS server retries [1-3]:  
>> RADIUS Server# time  
< server retries>  
Current RADIUS server timeout: 3  
Enter new RADIUS server timeout [1-10]: 10(Enter the timeout period in minutes)  
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RADIUS Authentication Features in Alteon OS  
Alteon OS supports the following RADIUS authentication features:  
Supports RADIUS client on the switch, based on the protocol definitions in RFC 2138 and  
RFC 2866.  
Allows RADIUS secret password up to 32 bytes and less than 16 octets.  
Supports secondary authentication server so that when the primary authentication server  
is unreachable, the switch can send client authentication requests to the secondary authen-  
tication server. Use the /cfg/sys/radius/curcommand to show the currently  
active RADIUS authentication server.  
Supports user-configurable RADIUS server retry and time-out values:  
Time-out value = 1-10 seconds  
Retries = 1-3  
The switch will time out if it does not receive a response from the RADIUS server in 1-3  
retries. The switch will also automatically retry connecting to the RADIUS server before it  
declares the server down.  
Supports user-configurable RADIUS application port.  
The default is 1645/UDP-based on RFC 2138. Port 1812 is also supported.  
Allows network administrator to define privileges for one or more specific users to access  
the switch at the RADIUS user database.  
SecurID is supported if the RADIUS server can do an ACE/Server client proxy. The pass-  
word is the PIN number, plus the token code of the SecurID card.  
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Switch User Accounts  
The user accounts listed in Table 1-2 can be defined in the RADIUS server dictionary file.  
Table 1-2 User Access Levels  
User Account  
Description and Tasks Performed  
Password  
User  
The User has no direct responsibility for switch management.  
He/she can view all switch status information and statistics but  
cannot make any configuration changes to the switch.  
user  
Operator  
The Operator manages all functions of the switch. The Operator oper  
can reset ports or the entire switch.  
Administrator  
The super-user Administrator has complete access to all menus, admin  
information, and configuration commands on the switch, includ-  
ing the ability to change both the user and administrator pass-  
words.  
RADIUS Attributes for Alteon OS User Privileges  
When the user logs in, the switch authenticates his/her level of access by sending the RADIUS  
access request, that is, the client authentication request, to the RADIUS authentication server.  
If the remote user is successfully authenticated by the authentication server, the switch will  
verify the privileges of the remote user and authorize the appropriate access. The administrator  
has an option to allow backdoor access via Telnet. The default is disablefor Telnet access.  
Backdoor access is always enabled on the console port.  
NOTE To obtain the RADIUS backdoor password for your GbESM, contact your IBM  
Service and Support line.  
All user privileges, other than those assigned to the Administrator, have to be defined in the  
RADIUS dictionary. RADIUS attribute 6 which is built into all RADIUS servers defines the  
administrator. The file name of the dictionary is RADIUS vendor-dependent. The following  
RADIUS attributes are defined for Alteon OS user privileges levels:  
Table 1-3 Alteon OS-proprietary Attributes for RADIUS  
User Name/Access  
User  
User-Service-Type  
Vendor-supplied  
Vendor-supplied  
Vendor-supplied  
Value  
255  
Operator  
Admin  
252  
250  
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TACACS+ Authentication  
Alteon OS supports authentication and authorization with networks using the Cisco Systems  
TACACS+ protocol. The GbE Switch Module functions as the Network Access Server (NAS)  
by interacting with the remote client and initiating authentication and authorization sessions  
with the TACACS+ access server. The remote user is defined as someone requiring manage-  
ment access to the GbE Switch Module either through a data or management port.  
TACACS+ offers the following advantages over RADIUS:  
TACACS+ uses TCP-based connection-oriented transport; whereas RADIUS is UDP-  
based. TCP offers a connection-oriented transport, while UDP offers best-effort delivery.  
RADIUS requires additional programmable variables such as re-transmit attempts and  
time-outs to compensate for best-effort transport, but it lacks the level of built-in support  
that a TCP transport offers.  
TACACS+ offers full packet encryption whereas RADIUS offers password-only encryp-  
tion in authentication requests.  
TACACS+ separates authentication, authorization and accounting.  
How TACACS+ Authentication Works  
TACACS+ works much in the same way as RADIUS authentication as described on page 44.  
1. Remote administrator connects to the switch and provides user name and password.  
2. Using Authentication/Authorization protocol, the switch sends request to authentication  
server.  
3. Authentication server checks the request against the user ID database.  
4. Using TACACS+ protocol, the authentication server instructs the switch to grant or deny  
administrative access.  
During a session, if additional authorization checking is needed, the switch checks with a  
TACACS+ server to determine if the user is granted permission to use a particular command.  
TACACS+ Authentication Features in Alteon OS  
Authentication is the action of determining the identity of a user, and is generally done when  
the user first attempts to log in to a device or gain access to its services. Alteon OS supports  
ASCII inbound login to the device. PAP, CHAP and ARAP login methods, TACACS+ change  
password requests, and one-time password authentication are not supported.  
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Authorization  
Authorization is the action of determining a user’s privileges on the device, and usually takes  
place after authentication.  
The default mapping between TACACS+ authorization levels and Alteon OS management  
access levels is shown in Table 1-4. The authorization levels must be defined on the TACACS+  
server.  
Table 1-4 Default TACACS+ Authorization Levels  
Alteon OS User Access Level  
TACACS+ level  
user  
oper  
admin  
0
3
6
Alternate mapping between TACACS+ authorization levels and Alteon OS management  
access levels is shown in Table 1-5. Use the command /cfg/sys/tacacs/cmap ena  
to use the alternate TACACS+ authorization levels.  
Table 1-5 Alternate TACACS+ Authorization Levels  
Alteon OS User Access Level  
TACACS+ level  
0 - 1  
user  
oper  
admin  
6 - 8  
14 - 15  
If the remote user is successfully authenticated by the authentication server, the switch verifies  
the privileges of the remote user and authorizes the appropriate access. The administrator has  
an option to allow backdoor access via Telnet (/cfg/sys/tacacs/telnet). The default  
value for Telnet access is disabled. The administrator also can enable secure backdoor  
(/cfg/sys/tacacs/secbd), to allow access if both the primary and the secondary  
TACACS+ servers fail to respond.  
NOTE To obtain the TACACS+ backdoor password for your GbESM, contact your IBM  
Service and Support line.  
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Accounting  
Accounting is the action of recording a user's activities on the device for the purposes of billing  
and/or security. It follows the authentication and authorization actions. If the authentication  
and authorization is not performed via TACACS+, there are no TACACS+ accounting mes-  
sages sent out.  
You can use TACACS+ to record and track software logins, configuration changes, and inter-  
active commands.  
The GbE Switch Module supports the following TACACS+ accounting attributes:  
protocol (console/telnet/ssh/http)  
start_time  
stop_time  
elapsed_time  
disc-cause  
NOTE When using the Browser-Based Interface, the TACACS+ Accounting Stop records are  
sent only if the Quit button on the browser is clicked.  
Command Authorization and Logging  
When TACACS+ Command Authorization is enabled (/cfg/sys/tacacs/cauth ena),  
Alteon OS configuration commands are sent to the TACACS+ server for authorization. When  
TACACS+ Command Logging is enabled (/cfg/sys/tacacs/clog ena), Alteon OS  
configuration commands are logged on the TACACS+ server.  
The following examples illustrate the format of Alteon OS commands sent to the TACACS+  
server:  
authorization request, cmd=cfgtree, cmd-arg=/cfg/l3/if  
accounting request, cmd=/cfg/l3/if, cmd-arg=1  
authorization request, cmd=cfgtree, cmd-arg=/cfg/l3/if/ena  
accounting request, cmd=/cfg/l3/if/ena  
authorization request, cmd=cfgtree, cmd-arg=/cfg/l3/if/addr  
accounting request, cmd=/cfg/l3/if/addr, cmd-arg=10.90.90.91  
authorization request, cmd=apply  
accounting request, cmd=apply  
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The following rules apply to TACACS+ command authorization and logging:  
Only commands from a Console, Telnet, or SSH connection are sent for authorization and  
logging. SNMP, BBI, or file-copy commands (for example, TFTP or sync) are not sent.  
Only leaf-level commands are sent for authorization and logging. For example, /cfgis  
not sent, but /cfg/l3/tacacs/cauthis sent.  
The full path of each command is sent for authorization and logging. For example,  
/cfg/sys/tacacs/cauth  
Command arguments are not sent for authorization. For /cauth ena, only /cauthis  
authorized. The command and its first argument are logged, if issued on the same line.  
Only executed commands are logged.  
Invalid commands are checked by Alteon OS, and are not sent for authorization or log-  
ging.  
Authorization is performed on each leaf-level command separately. If the user issues mul-  
tiple commands at once, each command is sent separately as a full path.  
Only the following global commands are sent for authorization and logging:  
apply  
diff  
ping  
revert  
save  
telnet  
traceroute  
TACACS+ Password Change  
Alteon OS supports TACACS+ password change. When enabled, users can change  
their passwords after successful TACACS+ authorization. Use the command  
/cfg/sys/tacacs/passchto enable or disable this feature.  
Use the following commands to change the password for the primary and secondary  
TACACS+ servers:  
>> # /cfg/sys/tacacs/chpass_p  
(Change primary TACACS+ password)  
(Change secondary TACACS+ password)  
>> # /cfg/sys/tacacs/chpass_s  
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Configuring TACACS+ Authentication on the Switch  
1. Turn TACACS+ authentication on, then configure the Primary and Secondary  
TACACS+ servers.  
>> Main# /cfg/sys/tacacs+  
>> TACACS+ Server# on  
Current status: OFF  
(Select the TACACS+ Server menu)  
(Turn TACACS+ on)  
New status:  
ON  
>> TACACS+ Server# prisrv 10.10.1.1  
(Enter primary server IP)  
Current primary TACACS+ server:  
0.0.0.0  
New pending primary TACACS+ server: 10.10.1.1  
>> TACACS+ Server# secsrv 10.10.1.2  
Current secondary TACACS+ server:  
(Enter secondary server IP)  
0.0.0.0  
New pending secondary TACACS+ server: 10.10.1.2  
2. Configure the TACACS+ secret and second secret.  
>> TACACS+ Server# secret  
Enter new TACACS+ secret: <1-32 character secret>  
>> TACACS+ Server# secret2  
Enter new TACACS+ second secret: <1-32 character secret>  
CAUTIONIf you configure the TACACS+ secret using any method other than a direct console  
connection or through a secure management module connection, the secret may be transmitted  
over the network as clear text.  
!
3. If desired, you may change the default TCP port number used to listen to TACACS+.  
The well-known port for TACACS+ is 49.  
>> TACACS+ Server# port  
Current TACACS+ port: 49  
Enter new TACACS+ port [1-65000]: <port number>  
4. Configure the number of retry attempts, and the timeout period.  
>> TACACS+ Server# retries  
Current TACACS+ server retries: 3  
Enter new TACACS+ server retries [1-3]:  
>> TACACS+ Server# time  
< server retries>  
Current TACACS+ server timeout: 5  
Enter new TACACS+ server timeout [4-15]: 10(Enter the timeout period in minutes)  
5. Apply and save the configuration.  
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LDAP Authentication and Authorization  
Alteon OS supports the LDAP (Lightweight Directory Access Protocol) method to authenti-  
cate and authorize remote administrators to manage the switch. LDAP is based on a client/  
server model. The switch acts as a client to the LDAP server. A remote user (the remote admin-  
istrator) interacts only with the switch, not the back-end server and database.  
LDAP authentication consists of the following components:  
A protocol with a frame format that utilizes TCP over IP  
A centralized server that stores all the user authorization information  
A client, in this case, the switch  
Each entry in the LDAP server is referenced by its Distinguished Name (DN). The DN consists  
of the user-account name concatenated with the LDAP domain name. If the user-account name  
is John, the following is an example DN:  
uid=John,ou=people,dc=domain,dc=com  
Configuring the LDAP Server  
GbESM user groups and user accounts must reside within the same domain. On the LDAP  
server, configure the domain to include GbESM user groups and user accounts, as follows:  
User Accounts:  
Use the uid attribute to define each individual user account.  
User Groups:  
Use the members attribute in the groupOfNames object class to create the user groups. The  
first word of the common name for each user group must be equal to the user group names  
defined in the GbESM, as follows:  
admin  
oper  
user  
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Configuring LDAP Authentication on the Switch  
1. Turn LDAP authentication on, then configure the Primary and Secondary LDAP servers.  
>> Main# /cfg/sys/ldap  
>> LDAP Server# on  
Current status: OFF  
(Select the LDAP Server menu)  
(Turn LDAP on)  
New status:  
ON  
>> LDAP Server# prisrv 10.10.1.1  
Current primary LDAP server:  
New pending primary LDAP server: 10.10.1.1  
>> LDAP Server# secsrv 10.10.1.2  
(Enter primary server IP)  
(Enter secondary server IP)  
0.0.0.0  
Current secondary LDAP server:  
0.0.0.0  
New pending secondary LDAP server: 10.10.1.2  
2. Configure the domain name.  
>> LDAP Server# domain  
Current LDAP domain name:  
Enter new LDAP domain name:  
ou-people,dc=domain,dc=com  
ou=people,dc=mydomain,dc=com  
3. If desired, you may change the default TCP port number used to listen to LDAP.  
The well-known port for LDAP is 389.  
>> LDAP Server# port  
Current LDAP port: 389  
Enter new LDAP port [1-65000]: <port number>  
4. Configure the number of retry attempts for contacting the LDAP server, and the timeout  
period.  
>> LDAP Server# retries  
Current LDAP server retries: 3  
Enter new LDAP server retries [1-3]:  
>> LDAP Server# timeout  
< server retries>  
Current LDAP server timeout: 5  
Enter new LDAP server timeout [4-15]: 10 (Enter the timeout period in minutes)  
5. Apply and save the configuration.  
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Secure Shell and Secure Copy  
Secure Shell (SSH) and Secure Copy (SCP) use secure tunnels to encrypt and secure messages  
between a remote administrator and the switch. Telnet does not provide this level of security.  
The Telnet method of managing a GbE Switch Module does not provide a secure connection.  
SSH is a protocol that enables remote administrators to log securely into the GbE Switch Mod-  
ule over a network to execute management commands.  
SCP is typically used to copy files securely from one machine to another. SCP uses SSH for  
encryption of data on the network. On a GbE Switch Module, SCP is used to download and  
upload the switch configuration via secure channels.  
The benefits of using SSH and SCP are listed below:  
Authentication of remote administrators  
Identifying the administrator using Name/Password  
Authorization of remote administrators  
Determining the permitted actions and customizing service for individual administrators  
Encryption of management messages  
Encrypting messages between the remote administrator and switch  
Secure copy support  
The Alteon OS implementation of SSH supports both versions 1.5 and 2.0. and supports SSH  
clients version 1.5 - 2.x. The following SSH clients have been tested  
SSH 1.2.23 and SSH 1.2.27 for Linux (freeware)  
SecureCRT 3.0.2 and SecureCRT 3.0.3 for Windows NT (Van Dyke Technologies, Inc.)  
F-Secure SSH 1.1 for Windows (Data Fellows)  
Putty SSH  
Cygwin OpenSSH  
Mac X OpenSSH  
Solaris 8 OpenSSH  
AxeSSH SSHPro  
SSH Communications Vandyke SSH A  
F-Secure  
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Configuring SSH/SCP features on the switch  
Before you can use SSH commands, use the following commands to turn on SSH/SCP. SSH  
and SCP are disabled by default.  
To enable or disable the SSH feature:  
Begin a Telnet session from the console port and enter the following commands:  
>> # /cfg/sys/sshd/on  
Current status: OFF  
New status: ON  
(Turn SSH on)  
>> # /cfg/sys/sshd/off  
Current status: ON  
New status: OFF  
(Turn SSH off)  
To enable or disable SCP apply and save:  
Enter the following commands from the switch CLI to enable the SCP putcfg_applyand  
putcfg_apply_savecommands:  
>> # /cfg/sys/sshd/ena  
SSHD# apply  
(Enable SCP apply and save)  
(Apply the changes to start generating RSA  
host and server keys)  
RSA host key generation starts  
.............................................................  
......................................................  
RSA host key generation completes (lasts 212549 ms)  
RSA host key is being saved to Flash ROM, please don't reboot  
the box immediately.  
RSA server key generation starts  
............................................................  
RSA server key generation completes (lasts 75503 ms)  
RSA server key is being saved to Flash ROM, please don't reboot  
the box immediately.  
------------------------------------------------------------------  
Apply complete; don't forget to "save" updated configuration.  
>> # /cfg/sys/sshd/dis  
(Disable SSH/SCP apply and save)  
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Configuring the SCP Administrator Password  
To configure the scpadm(SCP Administrator) password, first connect to the switch via the  
serial console port. For security reasons, the scpadm password may only be configured when  
connected through the console port.  
To configure the password, enter the following command via the CLI. At factory default set-  
tings, the current SCP administrator password is admin.  
>> /cfg/sys/sshd/scpadm  
Changing SCP-only Administrator password; validation required...  
Enter current administrator password: <password>  
Enter new SCP-only administrator password: <new password>  
Re-enter new SCP-only administrator password: <new password>  
New SCP-only administrator password accepted.  
Using SSH and SCP Client Commands  
This section shows the format for using some client commands. The examples below use  
205.178.15.157 as the IP address of a sample switch.  
To log in to the switch:  
Syntax:  
ssh <switch IP address> or ssh -l <login-name> <switch IP address>  
Example:  
>> # ssh 205.178.15.157  
>> # ssh -l <login-name> 205.178.15.157  
(Login to the switch)  
To download the switch configuration using SCP:  
Syntax:  
scp <username>@<switch IP address>:getcfg <local filename>  
Example:  
>> # scp scpadmin@205.178.15.157:getcfg ad4.cfg  
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To upload the configuration to the switch:  
Syntax:  
scp <local filename> <username>@<switch IP address>:putcfg  
Example:  
>> # scp ad4.cfg scpadmin@205.178.15.157:putcfg  
To apply and save the configuration  
The applyand savecommands are still needed after the last command, or use the following  
commands:  
>> # scp ad4.cfg scpadmin@205.178.15.157:putcfg_apply  
>> # scp ad4.cfg scpadmin@205.178.15.157:putcfg_apply_save  
The diffcommand is automatically executed at the end of putcfgto notify the remote  
client of the difference between the new and the current configurations.  
putcfg_applyruns the apply commandafter the putcfgis done.  
putcfg_apply_savesaves the new configuration to the flash after putcfg_apply  
is done.  
The putcfg_applyand putcfg_apply_savecommands are provided because  
extra applyand savecommands are usually required after a putcfg; however, an  
SCP session is not in an interactive mode at all.  
SSH and SCP Encryption of Management Messages  
The following encryption and authentication methods are supported for SSH and SCP:  
Server Host Authentication:  
Client RSA authenticates the switch at the beginning of  
every connection  
Key Exchange:  
Encryption:  
RSA  
3DES-CBC, DES  
User Authentication:  
Local password authentication, RADIUS, SecurID  
(via RADIUS, TACACS+, for SSH only—does not apply  
to SCP)  
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Generating RSA Host and Server Keys for SSH Access  
To support the SSH server feature, two sets of RSA keys (host and server keys) are required.  
The host key is 1024 bits and is used to identify the GbE Switch Module. The server key is 768  
bits and is used to make it impossible to decipher a captured session by breaking into the GbE  
Switch Module at a later time.  
When the SSH server is first enabled and applied, the switch automatically generates the RSA  
host and server keys and is stored in the FLASH memory.  
NOTE To configure RSA host and server keys, first connect to the GbE Switch Module  
through the console port (commands are not available via external Telnet connection), and  
enter the following commands to generate them manually.  
>> # /cfg/sys/sshd/hkeygen  
>> # /cfg/sys/sshd/skeygen  
(Generates the host key)  
(Generates the server key)  
These two commands take effect immediately without the need of an applycommand.  
When the switch reboots, it will retrieve the host and server keys from the FLASH memory. If  
these two keys are not available in the flash and if the SSH server feature is enabled, the switch  
automatically generates them during the system reboot. This process may take several minutes  
to complete.  
The switch can also automatically regenerate the RSA server key. To set the interval of RSA  
server key autogeneration, use this command:  
>> # /cfg/sys/sshd/intrval <number of hours (0-24)>  
A value of 0 (zero) denotes that RSA server key autogeneration is disabled. When greater than  
0, the switch will autogenerate the RSA server key every specified interval; however, RSA  
server key generation is skipped if the switch is busy doing other key or cipher generation  
when the timer expires.  
NOTE The switch will perform only one session of key/cipher generation at a time. Thus, an  
SSH/SCP client will not be able to log in if the switch is performing key generation at that  
time, or if another client has logged in immediately prior. Also, key generation will fail if an  
SSH/SCP client is logging in at that time.  
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SSH/SCP Integration with Radius Authentication  
SSH/SCP is integrated with RADIUS authentication. After the RADIUS server is enabled on  
the switch, all subsequent SSH authentication requests will be redirected to the specified  
RADIUS servers for authentication. The redirection is transparent to the SSH clients.  
SSH/SCP Integration with TACACS+ Authentication  
SSH/SCP is integrated with TACACS+ authentication. After the TACACS+ server is enabled  
on the switch, all subsequent SSH authentication requests will be redirected to the specified  
TACACS+ servers for authentication. The redirection is transparent to the SSH clients.  
SecurID Support  
SSH/SCP can also work with SecurID, a token card-based authentication method. The use of  
SecurID requires the interactive mode during login, which is not provided by the SSH connec-  
tion.  
NOTE There is no SNMP or Browser-Based Interface (BBI) support for SecurID because the  
SecurID server, ACE, is a one-time password authentication and requires an interactive ses-  
sion.  
Using SecurID with SSH  
Using SecurID with SSH involves the following tasks.  
To log in using SSH, use a special username, “ace,” to bypass the SSH authentication.  
After an SSH connection is established, you are prompted to enter the username and pass-  
word (the SecurID authentication is being performed now).  
Provide your username and the token in your SecurID card as a regular Telnet user.  
Using SecurID with SCP  
Using SecurID with SCP can be accomplished in two ways:  
Using a RADIUS server to store an administrator password.  
You can configure a regular administrator with a fixed password in the RADIUS server if  
it can be supported. A regular administrator with a fixed password in the RADIUS server  
can perform both SSH and SCP with no additional authentication required.  
Using an SCP-only administrator password.  
Use the command, /cfg/sys/sshd/scpadmto bypass the checking of SecurID.  
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An SCP-only administrator’s password is typically used when SecurID is used. For exam-  
ple, it can be used in an automation program (in which the tokens of SecurID are not avail-  
able) to back up (download) the switch configurations each day.  
NOTE The SCP-only administrator’s password must be different from the regular administra-  
tor’s password. If the two passwords are the same, the administrator using that password will  
not be allowed to log in as an SSH user because the switch will recognize him as the SCP-only  
administrator. The switch will only allow the administrator access to SCP commands.  
End User Access Control  
Alteon OS allows an administrator to define end user accounts that permit end users to perform  
operation tasks via the switch CLI commands. Once end user accounts are configured and  
enabled, the switch requires username/password authentication.  
For example, an administrator can assign a user, who can then log into the switch and perform  
operational commands (effective only until the next switch reboot).  
Considerations for Configuring End User Accounts  
A maximum of 10 user IDs are supported on the switch.  
Alteon OS supports end user support for Console, Telnet, BBI, and SSHv1/v2 access to  
the switch. As a result, only very limited access will be granted to the Primary Administra-  
tor under the BBI/SSH1 mode of access.  
If RADIUS authentication is used, the user password on the Radius server will override  
the user password on the GbE Switch Module. Also note that the password change com-  
mand on the switch only modifies the use switch password and has no effect on the user  
password on the Radius server. Radius authentication and user password cannot be used  
concurrently to access the switch.  
Passwords can be up to 15 characters in length for TACACS, RADIUS, Telnet, SSH, Con-  
sole, and Web access.  
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Strong Passwords  
The administrator can require use of Strong Passwords for users to access the GbESM. Strong  
Passwords enhance security because they make password guessing more difficult.  
The following rules apply when Strong Passwords are enabled:  
Each passwords must be 8 to 14 characters  
Within the first 8 characters, the password:  
must have at least one number or one symbol  
must have both upper and lower case letters  
cannot be the same as any four previously used passwords  
The following are examples of strong passwords:  
1234AbcXyz  
Super+User  
Exo1cet2  
The administrator can choose the number of days allowed before each password expires. When  
a strong password expires, the user is allowed to log in one last time (last time) to change the  
password. A warning provides advance notice for users to change the password.  
Use the Strong Password menu to configure Strong Passwords.  
>> # /cfg/sys/access/user/strongpw  
User Access Control Menu  
The end user access control menu is located in the System access menu.  
>> # /cfg/sys/access/user  
Setting up User IDs  
Up to 10 user IDs can be configured in the User ID menu.  
>> # /cfg/sys/access/user/uid 1  
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Defining User Names and Passwords  
Use the User ID menu to define user names and passwords.  
>> User ID 1 # name user1  
(Assign name to user ID 1)  
Current user name:  
New user name:  
user1  
>> User ID 1 # passwd  
(Assign password to user ID 1)  
Changing user password; validation required:  
Enter current admin password: <current administrator password>  
Enter new user1 password: <new user password>  
Re-enter new user1 password: <new user password>  
New user1 password accepted.  
Defining a User’s Access Level  
The end user is by default assigned to the user access level (also known as class of service, or  
CoS). CoS for all user accounts have global access to all resources except for User CoS, which  
has access to view only resources that the user owns. For more information, see Table 1-2  
“User Access Levels” on page 47.  
To change the user’s level, enter the class of service coscommand, and select one of the fol-  
lowing options:  
>> User ID 1 # cos <user|oper|admin>  
Validating a User’s Configuration  
User ID 2 # cur  
name jane  
, dis, cos user  
, password valid, offline  
Enabling or Disabling a User  
An end user account must be enabled before the switch recognizes and permits login under the  
account. Once enabled, the switch requires any user to enter both username and password.  
>> # /cfg/sys/access/user/uid<#>/ena  
>> # /cfg/sys/access/user/uid<#>/dis  
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Listing Current Users  
The curcommand displays defined user accounts and whether or not each user is currently  
logged into the switch.  
# /cfg/sys/access/user/cur  
Usernames:  
user  
oper  
admin  
- Enabled - offline  
- Disabled - offline  
- Always Enabled - online 1 session  
Current User ID table:  
1: name jane  
2: name john  
, ena, cos user  
, ena, cos user  
, password valid, online  
, password valid, online  
Logging into an End User Account  
Once an end user account is configured and enabled, the user can login to the switch username/  
password combination. The level of switch access is determined by the CoS established for the  
end user account.  
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CHAPTER 2  
Port-based Network Access Control  
Port-Based Network Access control provides a means of authenticating and authorizing  
“Extensible Authentication Protocol over LAN” on page 68  
“802.1x Authentication Process” on page 69  
“802.1x Port States” on page 71  
“Supported RADIUS Attributes” on page 72  
“Configuration Guidelines” on page 73  
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Extensible Authentication Protocol over LAN  
Alteon OS can provide user-level security for its ports using the IEEE 802.1x protocol, which  
is a more secure alternative to other methods of port-based network access control. Any device  
attached to an 802.1x-enabled port that fails authentication is prevented access to the network  
and denied services offered through that port.  
The 802.1x standard describes port-based network access control using Extensible Authentica-  
tion Protocol over LAN (EAPoL). EAPoL provides a means of authenticating and authorizing  
devices attached to a LAN port that has point-to-point connection characteristics and of pre-  
venting access to that port in cases of authentication and authorization failures.  
EAPoL is a client-server protocol that has the following components:  
Supplicant or Client  
The Supplicant is a device that requests network access and provides the required creden-  
tials (user name and password) to the Authenticator and the Authenticator Server.  
Authenticator  
The Authenticator enforces authentication and controls access to the network. The  
Authenticator grants network access based on the information provided by the Supplicant  
and the response from the Authentication Server. The Authenticator acts as an intermedi-  
ary between the Supplicant and the Authentication Server: requesting identity information  
from the client, forwarding that information to the Authentication Server for validation,  
relaying the server’s responses to the client, and authorizing network access based on the  
results of the authentication exchange. The GbESM acts as an Authenticator.  
Authentication Server,  
The Authentication Server validates the credentials provided by the Supplicant to deter-  
mine if the Authenticator should grant access to the network. The Authentication Server  
may be co-located with the Authenticator. The GbESM relies on external RADIUS servers  
for authentication.  
Upon a successful authentication of the client by the server, the 802.1x-controlled port transi-  
tions from unauthorized to authorized state, and the client is allowed full access to services  
through the port. When the client sends an EAP-Logoff message to the authenticator, the port  
will transition from authorized to unauthorized state.  
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802.1x Authentication Process  
The clients and authenticators communicate using Extensible Authentication Protocol (EAP),  
which was originally designed to run over PPP, and for which the IEEE 802.1x Standard has  
defined an encapsulation method over Ethernet frames, called EAP over LAN (EAPOL).  
Figure 2-1 shows a typical message exchange initiated by the client.  
RADIUS  
Server  
802.1x Client  
EAPOL  
GbESM  
(Authenticator)  
(RADIUS Client)  
RADIUS-EAP  
UDP/IP  
Ethernet  
Port Unauthorized  
EAPOL-Start  
EAP-Request (Credentials)  
EAP-Response (Credentials)  
Radius-Access-Request  
Radius-Access-Challenge  
EAP-Request (Credentials)  
EAP-Response (Credentials)  
Radius-Access-Request  
Radius-Access-Accept  
EAP-Success  
Port Authorized  
Figure 2-1 Authenticating a Port Using EAPoL  
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EAPoL Message Exchange  
During authentication, EAPOL messages are exchanged between the client and the GbESM  
authenticator, while RADIUS-EAP messages are exchanged between the GbESM authentica-  
tor and the RADIUS server.  
Authentication is initiated by one of the following methods:  
GbESM authenticator sends an EAP-Request/Identity packet to the client  
Client sends an EAPOL-Start frame to the GbESM authenticator, which responds with an  
EAP-Request/Identity frame.  
The client confirms its identity by sending an EAP-Response/Identity frame to the GbESM  
authenticator, which forwards the frame encapsulated in a RADIUS packet to the server.  
The RADIUS authentication server chooses an EAP-supported authentication algorithm to  
verify the client’s identity, and sends an EAP-Request packet to the client via the GbESM  
authenticator. The client then replies to the RADIUS server with an EAP-Response containing  
its credentials.  
Upon a successful authentication of the client by the server, the 802.1x-controlled port transi-  
tions from unauthorized to authorized state, and the client is allowed full access to services  
through the controlled port. When the client later sends an EAPOL-Logoff message to the  
GbESM authenticator, the port transitions from authorized to unauthorized state.  
If a client that does not support 802.1x connects to an 802.1x-controlled port, the GbESM  
authenticator requests the client's identity when it detects a change in the operational state of  
the port. The client does not respond to the request, and the port remains in the unauthorized  
state.  
NOTE When an 802.1x-enabled client connects to a port that is not 802.1x-controlled, the cli-  
ent initiates the authentication process by sending an EAPOL-Start frame. When no response is  
received, the client retransmits the request for a fixed number of times. If no response is  
received, the client assumes the port is in authorized state, and begins sending frames, even if  
the port is unauthorized.  
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802.1x Port States  
The state of the port determines whether the client is granted access to the network, as follows:  
Unauthorized  
While in this state the port discards all ingress and egress traffic except EAP packets.  
Authorized  
When the client is successfully authenticated, the port transitions to the authorized state  
allowing all traffic to and from the client to flow normally.  
Force Unauthorized  
You can configure this state that denies all access to the port.  
Force Authorized  
You can configure this state that allows full access to the port.  
Use the 802.1x Global Configuration Menu (/cfg/l2/8021x/global) to  
configure 802.1x authentication for all ports in the switch. Use the 802.1x Port Menu  
(/cfg/l2/8021x/port x) to configure a single port.  
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Supported RADIUS Attributes  
The Alteon 802.1x Authenticator relies on external RADIUS servers for authentication  
with EAP. Table 2 lists the RADIUS attributes that are supported as part of  
RADIUS-EAP authentication based on the guidelines specified in Annex D of the 802.1x  
standard and RFC 3580.  
Table 2 Support for RADIUS Attributes  
#
Attribute  
Attribute Value  
A-R A-A A-C A-R  
1
User-Name  
The value of the Type-Data field from the supplicant’s  
EAP-Response/Identity message. If the Identity is  
unknown (i.e. Type-Data field is zero bytes in length), this  
attribute will have the same value as the Calling-Station-  
Id.  
1
0-1  
0
0
4
5
NAS-IP-Address  
NAS-Port  
IP address of the authenticator used for Radius commu-  
nication.  
1
1
0
0
0
0
0
0
0
Port number of the authenticator port to which the suppli-  
cant is attached.  
24 State  
Server-specific value. This is sent unmodified back to the 0-1  
server in an Access-Request that is in response to an  
Access-Challenge.  
0-1 0-1  
30 Called-Station-ID  
31 Calling-Station-ID  
79 EAP-Message  
The MAC address of the authenticator encoded as an  
ASCII string in canonical format, e.g. 000D5622E3 9F.  
1
0
0
0
0
0
0
The MAC address of the supplicant encoded as an ASCII  
string in canonical format, e.g. 00034B436206.  
1
Encapsulated EAP packets from the supplicant to the  
authentication server (Radius) and vice-versa. The  
authenticator relays the decoded packet to both devices.  
1+  
1+  
1+  
1+  
80 Message-Authentica- Always present whenever an EAP-Message attribute is  
1
1
1
0
1
0
1
0
tor  
also included. Used to integrity-protect a packet.  
87 NAS-Port-ID  
Name assigned to the authenticator port, e.g.  
Server1_Port3  
Legend:  
RADIUS Packet Types: A-R (Access-Request), A-A (Access-Accept), A-C (Access-Challenge), A-R (Access-Reject)  
RADIUS Attribute Support:  
0
This attribute MUST NOT be present in a packet.  
0+ Zero or more instances of this attribute MAY be present in a packet.  
0-1 Zero or one instance of this attribute MAY be present in a packet.  
1
Exactly one instance of this attribute MUST be present in a packet.  
1+ One or more of these attributes MUST be present.  
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Configuration Guidelines  
When configuring EAPoL, consider the following guidelines:  
The 802.1x port-based authentication is currently supported only in point-to-point config-  
urations, that is, with a single supplicant connected to an 802.1x-enabled switch port.  
When 802.1x is enabled, a port has to be in the authorized state before any other Layer 2  
feature can be operationally enabled. For example, the STG state of a port is operationally  
disabled while the port is in the unauthorized state.  
The 802.1x supplicant capability is not supported. Therefore, none of its ports can suc-  
cessfully connect to an 802.1x-enabled port of another device, such as another switch, that  
acts as an authenticator, unless access control on the remote port is disabled or is config-  
ured in forced-authorized mode. For example, if a GbESM is connected to another  
GbESM, and if 802.1x is enabled on both switches, the two connected ports must be con-  
figured in force-authorized mode.  
The 802.1x standard has optional provisions for supporting dynamic virtual LAN  
assignment via RADIUS tunnelling attributes, for example, Tunnel-Type (=VLAN),  
Tunnel-Medium-Type (=802), and Tunnel-Private-Group-ID (=VLAN id).  
These attributes are not supported and might affect 802.1x operations. Other unsupported  
attributes include Service-Type, Session-Timeout, and Termination-Action.  
RADIUS accounting service for 802.1x-authenticated devices or users is not supported.  
Configuration changes performed using SNMP and the standard 802.1x MIB will take  
effect immediately.  
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CHAPTER 3  
VLANs  
This chapter describes network design and topology considerations for using Virtual Local Area  
Networks (VLANs). VLANs are commonly used to split up groups of network users into man-  
policies among logical segments. The following topics are discussed in this chapter:  
“VLANs and Port VLAN ID Numbers” on page 77  
“VLAN Tagging” on page 80  
“VLAN Topologies and Design Considerations” on page 84  
This section discusses how you can logically connect users and segments to a host that  
supports many logical segments or subnets by using the flexibility of the multiple VLAN  
system.  
“Protocol-based VLANs” on page 87  
NOTE Basic VLANs can be configured during initial switch configuration (see “Using the  
Setup Utility” in the Alteon OS Command Reference). More comprehensive VLAN configura-  
tion can be done from the Command Line Interface (see “VLAN Configuration” as well as  
“Port Configuration” in the Alteon OS Command Reference).  
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Overview  
Setting up virtual LANs (VLANs) is a way to segment networks to increase network flexibility  
without changing the physical network topology. With network segmentation, each switch port  
connects to a segment that is a single broadcast domain. When a switch port is configured to be  
a member of a VLAN, it is added to a group of ports (workgroup) that belong to one broadcast  
domain.  
Ports are grouped into broadcast domains by assigning them to the same VLAN. Frames  
received in one VLAN can only be forwarded within that VLAN, and multicast, broadcast,  
and unknown unicast frames are flooded only to ports in the same VLAN. The GbE Switch  
Module supports jumbo frames, up to 12288 bytes.  
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VLANs and Port VLAN ID Numbers  
VLAN Numbers  
Alteon OS supports up to 1024 VLANs per switch. Even though the maximum number  
of VLANs supported at any given time is 1024, each can be identified with any number  
between 1 and 4095. VLAN 1 is the default VLAN for the external ports and the internal blade  
ports. VLAN 4095 is reserved for use by the internal management ports (MGT1 and MGT2).  
VLAN 4094 is reserved for use by the external management port (EXT7).  
Viewing VLANs  
VLAN information menu:  
VLAN  
Name  
Status  
Ports  
---- ------------------------ ------ -------------------------  
1
2
Default VLAN  
VLAN 2  
ena  
dis  
ena  
ena  
INT1-INT14 EXT1-EXT6  
empty  
EXT7  
MGT1-MGT2  
4094 EXT-Mgmt VLAN  
4095 Mgmt VLAN  
PVLAN Protocol FrameType EtherType Priority Status  
Ports  
----- -------- -------------------- -------- ------ -----------  
1
2
empty  
0000  
0
dis  
empty  
PVLAN  
PVLAN-Tagged Ports  
----- ---------------------------  
none none  
NOTE The sample screens that appear in this document might differ slightly from the screens  
displayed by your system. Screen content varies based on the type of BladeCenter unit that you  
are using and the firmware versions and options that are installed.  
PVID Numbers  
Each port in the switch has a configurable default VLAN number, known as its PVID. By  
default, the PVID for all non-management ports is set to 1, which correlates to the default  
VLAN ID. The PVID for each port can be configured to any VLAN number between 1 and  
4094.  
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Viewing and Configuring PVIDs  
Use the following CLI commands to view PVIDs:  
Port information:  
Alias Port Tag Fast PVID  
NAME  
VLAN(s)  
----- ---- --- ---- ---- -------------- ----------------------------  
---  
INT1  
INT2  
INT3  
INT4  
INT5  
INT6  
INT7  
INT8  
INT9  
1 n n  
2 n n  
3 n n  
4 n n  
5 n n  
6 n n  
7 n n  
8 n n  
9 n n  
1 INT1  
1 INT2  
1 INT3  
1 INT4  
1 INT5  
1 INT6  
1 INT7  
1 INT8  
1 INT9  
1 INT10  
1 INT11  
1 INT12  
1 INT13  
1 INT14  
1
1
1
1
1
1
1
1
1
1
1
1
1
1
INT10 10 n n  
INT11 11 n n  
INT12 12 n n  
INT13 13 n n  
INT14 14 n n  
MGT1 15 n n 4095 MGT1  
MGT2 16 n n 4095 MGT2  
4095  
4095  
EXT1 17 n n  
EXT2 18 n n  
EXT3 19 n n  
EXT4 20 n n  
EXT5 21 n n  
EXT6 22 n n  
1 EXT1  
1 EXT2  
1 EXT3  
1 EXT4  
1 EXT5  
1 EXT6  
1
1
1
1
1
1
EXT7 23 n n 4094 EXT7  
4094  
* = PVID is tagged.  
NOTE The sample screens that appear in this document might differ slightly from the screens  
displayed by your system. Screen content varies based on the type of BladeCenter unit that you  
are using and the firmware versions and options that are installed.  
Port Configuration:  
>> /cfg/port INT7/pvid 7  
Current port VLAN ID:  
1
New pending port VLAN ID: 7  
>> Port INT7#  
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Each port on the switch can belong to one or more VLANs, and each VLAN can have any  
number of switch ports in its membership. Any port that belongs to multiple VLANs, however,  
must have VLAN tagging enabled (see “VLAN Tagging” on page 80).  
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VLAN Tagging  
Alteon OS software supports 802.1Q VLAN tagging, providing standards-based VLAN sup-  
port for Ethernet systems.  
Tagging places the VLAN identifier in the frame header of a packet, allowing each port to  
belong to multiple VLANs. When you add a port to multiple VLANs, you also must enable  
tagging on that port.  
Since tagging fundamentally changes the format of frames transmitted on a tagged port, you  
must carefully plan network designs to prevent tagged frames from being transmitted to  
devices that do not support 802.1Q VLAN tags, or devices where tagging is not enabled.  
Important terms used with the 802.1Q tagging feature are:  
VLAN identifier (VID)—the 12-bit portion of the VLAN tag in the frame header that  
identifies an explicit VLAN.  
Port VLAN identifier (PVID)—a classification mechanism that associates a port with a  
specific VLAN. For example, a port with a PVID of 3 (PVID =3) assigns all untagged  
frames received on this port to VLAN 3. Any untagged frames received by the switch are  
classified with the PVID of the receiving port.  
Tagged frame—a frame that carries VLAN tagging information in the header. This VLAN  
tagging information is a 32-bit field (VLAN tag) in the frame header that identifies the  
frame as belonging to a specific VLAN. Untagged frames are marked (tagged) with this  
classification as they leave the switch through a port that is configured as a tagged port.  
Untagged frame— a frame that does not carry any VLAN tagging information in the  
frame header.  
Untagged member—a port that has been configured as an untagged member of a specific  
VLAN. When an untagged frame exits the switch through an untagged member port, the  
frame header remains unchanged. When a tagged frame exits the switch through an  
untagged member port, the tag is stripped and the tagged frame is changed to an untagged  
frame.  
Tagged member—a port that has been configured as a tagged member of a specific  
VLAN. When an untagged frame exits the switch through a tagged member port, the  
frame header is modified to include the 32-bit tag associated with the PVID. When a  
tagged frame exits the switch through a tagged member port, the frame header remains  
unchanged (original VID remains).  
NOTE If a 802.1Q tagged frame is received by a port that has VLAN-tagging disabled, then  
the frame is dropped at the ingress port.  
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Figure 3-1 Default VLAN settings  
802.1Q Switch  
VLAN 1  
Port 1  
Port 2  
Port 3  
Port 4  
Port 5  
Port 6  
...  
Port 7  
PVID = 1  
DA  
SA  
CRC  
Data  
Incoming  
untagged  
packet  
Outgoing  
untagged packet  
(unchanged)  
Data  
CRC  
SA  
DA  
Key  
By default:  
All ports are assigned PVID = 1  
All external ports are untagged members of VLAN 1  
All internal server ports are untagged members of VLAN 1  
NOTE The port numbers specified in these illustrations may not directly correspond to the  
physical port configuration of your switch model.  
When a VLAN is configured, ports are added as members of the VLAN, and the ports are  
defined as either tagged or untagged (see Figure 3-2 through Figure 3-5).  
In Figure 3-1, untagged incoming packets are assigned directly to VLAN 2 (PVID = 2). Port 5  
is configured as a tagged member of VLAN 2, and port 7 is configured as an untagged member  
of VLAN 2.  
The default configuration settings for GbE Switch Modules have all ports set as untagged  
members of VLAN 1 with all ports configured as PVID = 1. In the default configuration exam-  
ple shown in Figure 3-1 on page 81, all incoming packets are assigned to VLAN 1 by the  
default port VLAN identifier (PVID =1).  
Figure 3-2 through Figure 3-5 illustrate generic examples of VLAN tagging.  
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NOTE The port assignments in the following figures are not meant to match the  
GbE Switch Module.  
Figure 3-2 Port-based VLAN assignment  
Port 1  
Port 2  
Port 3  
Tagged member  
of VLAN 2  
PVID = 2  
Untagged packet  
802.1Q Switch  
CRC Data SA DA  
Before  
Port 6  
Port 7  
Port 8  
Untagged member  
of VLAN 2  
BS45011A  
As shown in Figure 3-3, the untagged packet is marked (tagged) as it leaves the switch through  
port 5, which is configured as a tagged member of VLAN 2. The untagged packet remains  
unchanged as it leaves the switch through port 7, which is configured as an untagged member  
of VLAN 2.  
Figure 3-3 802.1Q tagging (after port-based VLAN assignment)  
Tagged member  
of VLAN 2  
PVID = 2  
Port 1  
Port 2  
Port 3  
802.1Q Switch  
CRC* Data Tag SA DA  
(*Recalculated)  
Port 6  
Port 7  
CRC  
Data  
Port 8  
8100 Priority CFI VID = 2  
Untagged memeber  
of VLAN 2  
16 bits 3 bits 1 bits 12 bits  
After  
SA  
DA  
Outgoing  
untagged packet  
(unchanged)  
Key  
Priority - User_priority  
CFI  
VID  
- Canonical format indicator  
- VLAN identifier  
BS45012A  
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In Figure 3-4, tagged incoming packets are assigned directly to VLAN 2 because of the tag  
assignment in the packet. Port 5 is configured as a tagged member of VLAN 2, and port 7 is  
configured as an untagged member of VLAN 2.  
Figure 3-4 802.1Q tag assignment  
Port 1  
Port 2  
Port 3  
Tagged member  
of VLAN 2  
PVID = 2  
Tagged packet  
802.1Q Switch  
CRC Data Tag SA DA  
Before  
Port 6  
Port 7  
Port 8  
Untagged member  
of VLAN 2  
BS45013A  
As shown in Figure 3-5, the tagged packet remains unchanged as it leaves the switch through  
port 5, which is configured as a tagged member of VLAN 2. However, the tagged packet is  
stripped (untagged) as it leaves the switch through port 7, which is configured as an untagged  
member of VLAN 2.  
Figure 3-5 802.1Q tagging (after 802.1Q tag assignment)  
PVID = 2  
Tagged member  
of VLAN 2  
Port 1  
Port 2  
Port 3  
802.1Q Switch  
CRC Data Tag SA DA  
Port 6  
Port 7  
Port 8  
8100 Priority CFI VID = 2  
Untagged member  
of VLAN 2  
(*Recalculated)  
CRC*  
Data  
16 bits 3 bits 1 bit 12 bits  
After  
Outgoing  
untagged packet  
changed  
SA  
DA  
Key  
Priority - User_priority  
(tag removed)  
CFI  
VID  
- Canonical format indicator  
- VLAN identifier  
BS45014A  
NOTE Set the configuration to factory default (/boot/conf factory) to reset all non-  
management ports to VLAN 1.  
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VLAN Topologies and Design Considerations  
By default, the Alteon OS software is configured so that tagging is disabled on all external  
ports and all internal ports.  
By default, the Alteon OS software is configured so that all internal ports are members of  
VLAN 1.  
By default, the Alteon OS software is configured so that the management ports (MGT1  
and MGT2) are members of the management VLAN 4095.  
By default, the Alteon OS software is configured so that the external management port  
(EXT7) is a member of VLAN 4094.  
If configuring Spanning Tree Groups (STG), note that Spanning Tree Groups 2-128 may  
contain only one VLAN.  
VLAN configuration rules  
VLANs operate according to specific configuration rules. When creating VLANs, consider the  
following rules that determine how the configured VLAN reacts in any network topology:  
All ports involved in trunking and port mirroring must have the same VLAN configura-  
tion. If a port is on a trunk with a mirroring port, the VLAN configuration cannot be  
changed. For more information trunk groups, see “Port Trunking Example” on page 97.  
All ports that are involved in port mirroring must have memberships in the same VLANs.  
If a port is configured for port mirroring, the port’s VLAN membership cannot be  
changed. For more information on configuring port mirroring, see “Monitoring Ports” on  
page 246.  
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Example 1: Multiple VLANs with Tagging Adapters  
BladeCenter  
VLAN #1, 2, 3  
VLAN #3  
GbE  
Switch Module  
Figure 3-6 Example 1: Multiple VLANs with VLAN-Tagged Gigabit Adapters  
The features of this VLAN are described below:  
Component  
Description  
GbE Switch  
Module  
This switch is configured for three VLANs that represent three differ-  
ent IP subnets. Two servers and five clients are attached to the switch.  
Server #1  
This server is a member of VLAN 3 and has presence in only one IP  
subnet. The associated internal switch port is only a member of VLAN  
3, so tagging is disabled.  
Server #2  
This high-use server needs to be accessed from all VLANs and IP sub-  
nets. The server has a VLAN-tagging adapter installed with VLAN tag-  
ging turned on. The adapter is attached to one of the internal switch  
ports, that is a member of VLANs 1, 2, and 3, and has tagging enabled.  
Because of the VLAN tagging capabilities of both the adapter and the  
switch, the server is able to communicate on all three IP subnets in this  
network. Broadcast separation between all three VLANs and subnets,  
however, is maintained.  
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Component  
Description  
PCs #1 and #2  
These PCs are attached to a shared media hub that is then connected to  
the switch. They belong to VLAN 2 and are logically in the same IP  
subnet as Server 2 and PC 5. The associated external switch port has  
tagging disabled.  
PC #3  
PC #4  
PC #5  
A member of VLAN 1, this PC can only communicate with Server 2  
and PC 5. The associated external switch port has tagging disabled.  
A member of VLAN 3, this PC can only communicate with Server 1  
and Server 2. The associated external switch port has tagging disabled.  
A member of both VLAN 1 and VLAN 2, this PC has a VLAN-tagging  
Gigabit Ethernet adapter installed. It can communicate with Server 2  
and PC 3 via VLAN 1, and to Server 2, PC 1 and PC 2 via VLAN 2.  
The associated external switch port is a member of VLAN 1 and  
VLAN 2, and has tagging enabled.  
NOTE VLAN tagging is required only on ports that are connected to other GbE Switch  
Modules or on ports that connect to tag-capable end-stations, such as servers with VLAN-  
tagging adapters.  
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Protocol-based VLANs  
Protocol-based VLANs (PVLANs) allow you to segment network traffic according to the net-  
work protocols in use. Traffic generated by supported network protocols can be confined to a  
particular port-based VLAN. You can give different priority levels to traffic generated by dif-  
ferent network protocols.  
With PVLAN, the switch classifies incoming packets by Ethernet protocol of the packets, not  
by the configuration of the ingress port. When an untagged or priority-tagged frame arrives at  
an ingress port, the protocol information carried in the frame is used to determine a VLAN to  
which the frame belongs. If a frame’s protocol is not recognized as a pre-defined PVLAN type,  
the ingress port’s PVID is assigned to the frame. When a tagged frame arrives, the VLAN ID in  
the frame’s tag is used.  
Each VLAN can contain up to eight different PVLANs. You can configure separate PVLANs  
on different VLANs, with each PVLAN segmenting traffic for the same protocol type. For  
example, you can configure PVLAN 1 on VLAN 2 to segment IPv4 traffic, and PVLAN 8 on  
VLAN 100 to segment IPv4 traffic.  
To define a PVLAN on a VLAN, configure a PVLAN number (1-8) and specify the frame type  
and the Ethernet type of the PVLAN protocol. You must assign at least one port to the PVLAN  
before it can function. Define the PVLAN frame type and Ethernet type as follows:  
Frame type—consists of one of the following values:  
Ether2 (Ethernet II)  
SNAP (Simple Network Access Protocol)  
LLC (Logical Link Control)  
Ethernet type—consists of a 4-digit (16 bit) hex value that defines the Ethernet type. You  
can use common Ethernet protocol values, or define your own values. Following are  
examples of common Ethernet protocol values:  
IPv4 = 0080  
IPv6 = 86dd  
ARP = 0806  
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Port-based vs. Protocol-based VLANs  
Each VLAN supports both port-based and protocol-based association, as follows:  
The default VLAN configuration is port-based. All data ports are members of VLAN 1,  
with no PVLAN association.  
When you add ports to a PVLAN, the ports become members of both the port-based  
VLAN and the PVLAN. For example, if you add port EXT1 to PVLAN 1 on VLAN 2, the  
port also becomes a member of VLAN 2.  
When you delete a PVLAN, it’s member ports remain members of the port-based VLAN.  
For example, if you delete PVLAN 1 from VLAN 2, port EXT1 remains a member of  
VLAN 2.  
When you delete a port from a VLAN, the port is deleted from all corresponding  
PVLANs.  
PVLAN Priority Levels  
You can assign each PVLAN a priority value of 0-7, used for Quality of Service (QoS).  
PVLAN priority takes precedence over a port’s configured priority level. If no priority level is  
configured for the PVLAN (priority = 0), each port’s priority is used (if configured).  
All member ports of a PVLAN have the same PVLAN priority level.  
PVLAN Tagging  
When PVLAN tagging is enabled, the switch tags frames that match the PVLAN protocol. For  
more information about tagging, see “VLAN Tagging” on page 80.  
Untagged ports must have PVLAN tagging disabled. Tagged ports can have PVLAN tagging  
either enabled or disabled.  
PVLAN tagging has higher precedence than port-based tagging. If a port is tag enabled  
(/cfg/port x/tag), and the port is a member of a PVLAN, the PVLAN tags egress  
frames that match the PVLAN protocol.  
Use the tag list command (/cfg/l2/vlan x/pvlan x/taglist) to define the com-  
plete list of tag-enabled ports in the PVLAN. Note that all ports not included in the PVLAN tag  
list will have PVLAN tagging disabled.  
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PVLAN Configuration Guidelines  
Consider the following guidelines when you configure protocol-based VLANs:  
Each port can support up to 16 VLAN protocols.  
The GbESM can support up to 16 protocols simultaneously.  
Each PVLAN must have at least one port assigned before it can be activated.  
The same port within a port-based VLAN can belong to multiple PVLANs.  
An untagged port can be a member of multiple PVLANs.  
A port cannot be a member of different VLANs with the same protocol association.  
Configuring PVLAN  
Follow this procedure to configure a Protocol-based VLAN (PVLAN).  
1. Create a VLAN and define the protocol type(s) supported by the VLAN.  
>> /cfg/l2/vlan 2  
>> VLAN 2# ena  
(Select VLAN 2)  
Current status: disabled  
New status:  
enabled  
>> VLAN 2# pvlan  
Enter protocol number [1-8]:1  
>> VLAN 2 Protocol 1# pty  
(Select a protocol number)  
Current FrameType: empty; EtherType: empty  
Enter new frame type(Ether2/SNAP/LLC): ether2 (Define the frame type)  
Enter new Ether type: 0800  
(Define the Ethernet type)  
New pending FrameType: Ether2; EtherType: 0800  
2. Configure the priority value for the protocol.  
>> VLAN 2 Protocol 1# prio  
(Configure the priority value)  
Current protocol priority: 0  
Enter new protocol priority [0-7]: 1  
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3. Add member ports for this PVLAN.  
>> VLAN 2 Protocol 1# add int1  
Port INT1 is an UNTAGGED port and its current PVID is 1.  
Confirm changing PVID from 1 to 2 [y/n]: y  
Current ports for VLAN 2:  
empty  
Current ports for VLAN 1, Protocol 3:  
Pending new ports for VLAN 2: INT1  
empty  
Pending new ports for VLAN 2, Protocol 1: INT1  
>> VLAN 2 Protocol 1# add ext1  
Port EXT1 is an UNTAGGED port and its current PVID is 1.  
Confirm changing PVID from 1 to 2 [y/n]: y  
Current ports for VLAN 2:  
empty  
Current ports for VLAN 1, Protocol 2:  
empty  
INT1 EXT1  
Pending new ports for VLAN 2:  
Pending new ports for VLAN 2, Protocol 1:  
INT1 EXT1  
4. Configure VLAN tagging for ports.  
>> VLAN 2 Protocol 1# /cfg/port int1/tag ena  
(Enable tagging on port)  
Current VLAN tag support: disabled  
New VLAN tag support:  
enabled  
Port INT1 changed to tagged.  
>> Port INT1# /cfg/l2/vlan 2/pvlan 1/tagpvl  
(Enable PVLAN tagging)  
Enter port to be tagged:  
Ena/Dis pvlan tag:  
int1  
ena  
Current status: disabled  
New status:  
enabled  
WARN: Tagging status of Port 1 in VLAN 2 will be changed for  
all protocols.  
Confirm changing port's pvlan tagging status [y/n]: y  
5. Enable the PVLAN.  
>> VLAN 2 Protocol 1# ena  
Current status: disabled  
(Enable the protocol-based VLAN)  
New status:  
enabled  
>> VLAN 2 Protocol 1# apply  
>> VLAN 2 Protocol 1# save  
(Apply the configuration)  
(Save your changes)  
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6. Verify PVLAN operation.  
>> /info/l2/vlan  
(View VLAN information)  
VLAN  
Name  
Status  
Ports  
---- ------------------------ ------ -------------------------  
1
2
Default VLAN  
VLAN 2  
ena  
ena  
ena  
ena  
INT1-INT14 EXT2-EXT6  
INT1 EXT1  
EXT7  
4094 EXT-Mgmt VLAN  
4095 Mgmt VLAN  
MGT1 MGT2  
PVLAN Protocol FrameType EtherType Priority Status  
Ports  
----- -------- -------------------- -------- ------ -----------  
2
1
Ether2  
0800  
0
ena  
INT1  
PVLAN  
PVLAN-Tagged Ports  
----- ---------------------------  
2
INT1 INT2  
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CHAPTER 4  
Ports and Trunking  
Trunk groups can provide super-bandwidth, multi-link connections between GbE Switch Mod-  
ules or other trunk-capable devices. A trunk group is a group of ports that act together, combin-  
background and examples for trunking multiple ports together:  
Overview” on this page  
“Port Trunking Example” on page 97  
“Configurable Trunk Hash Algorithm” on page 100  
“Link Aggregation Control Protocol” on page 101  
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Overview  
When using port trunk groups between two switches, as shown in Figure 4-1, you can create a  
virtual link between the switches, operating up to 60Gb per second, depending on how many  
physical ports are combined. Each GbESM supports up to 13 trunk groups, and each trunk  
group can contain up to six member ports.  
BladeCenter  
Aggregate  
port trunk  
Alteon Application Switch  
Figure 4-1 Port Trunk Group  
Trunk groups are also useful for connecting a GbE Switch Module to third-party devices that  
support link aggregation, such as Cisco routers and switches with EtherChannel technology  
(not ISL trunking technology) and Sun's Quad Fast Ethernet Adapter. Trunk Group technology  
is compatible with these devices when they are configured manually.  
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Statistical Load Distribution  
Network traffic is statistically distributed between the ports in a trunk group. The Alteon OS-  
powered switch uses the Layer 2 MAC address information present in each transmitted frame  
for determining load distribution.  
Each packet’s particular combination of source and destination MAC addresses results in  
selecting one line in the trunk group for data transmission. If there are enough Layer 2 devices  
feeding the trunk lines, then traffic distribution becomes relatively even.  
Built-In Fault Tolerance  
Since each trunk group is comprised of multiple physical links, the trunk group is inherently  
fault tolerant. As long as one connection between the switches is available, the trunk remains  
active.  
Statistical load balancing is maintained whenever a port in a trunk group is lost or returned to  
service.  
Before you configure static trunks  
When you create and enable a static trunk, the trunk members (switch ports) take on certain  
settings necessary for correct operation of the trunking feature.  
Before you configure your trunk, you must consider these settings, along with specific config-  
uration rules, as follows:  
1. Read the configuration rules provided in the section, “Trunk group configuration rules”  
on page 96.”  
2. Determine which switch ports (up to six) are to become trunk members (the specific ports  
Ensure that the chosen switch ports are set to enabled, using the /cfg/portcommand.  
Trunk member ports must have the same VLAN configuration.  
3. Consider how the existing Spanning Tree will react to the new trunk configuration. See  
Chapter 5, “Spanning Tree Group” for Spanning Tree Group configuration guidelines.  
4. Consider how existing VLANs will be affected by the addition of a trunk.  
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Trunk group configuration rules  
The trunking feature operates according to specific configuration rules. When creating trunks,  
consider the following rules that determine how a trunk group reacts in any network topology:  
All trunks must originate from one device, and lead to one destination device. For exam-  
ple, you cannot combine a link from Server 1 and a link from Server 2, into one trunk  
group.  
Any physical switch port can belong to only one trunk group.  
Trunking from third-party devices must comply with Cisco® EtherChannel® technology.  
All trunk member ports must be assigned to the same VLAN configuration before the  
trunk can be enabled.  
If you change the VLAN settings of any trunk member, you cannot apply the change until  
you change the VLAN settings of all trunk members.  
When an active port is configured in a trunk, the port becomes a trunk member when you  
enable the trunk using the /cfg/l2/trunk/ena command. The Spanning Tree  
parameters for the port then change to reflect the new trunk settings.  
All trunk members must be in the same Spanning Tree Group (STG) and can belong to  
only one Spanning Tree Group (STG). However if all ports are tagged, then all trunk ports  
can belong to multiple STGs.  
If you change the Spanning Tree participation of any trunk member to enabledor dis-  
abled, the Spanning Tree participation of all members of that trunk changes similarly.  
When a trunk is enabled, the trunk Spanning Tree participation setting takes precedence  
over that of any trunk member.  
You cannot configure a trunk member as a monitor port in a port-mirroring configuration.  
Trunks cannot be monitored by a monitor port; however, trunk members can be moni-  
tored.  
To guarantee proper trunking behavior, all ports in static trunks must be configured for  
full-duplex mode (cfg/port x/gig/mode full).  
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Port Trunking Example  
In the example below, three ports are trunked between two switches.  
Alteon Application Switch  
Trunk 3: Potrs 2, 12, and 22  
Trunk 1: Potrs EXT1, EXT2, and EXT3  
GbE Swicth  
Module  
BladeCenter  
Figure 4-2 Port Trunk Group Configuration Example  
Prior to configuring each switch in the above example, you must connect to the appropriate  
switch’s Command Line Interface (CLI) as the administrator.  
NOTE For details about accessing and using any of the menu commands described in this  
example, see the Alteon OS Command Reference.  
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1. Connect the switch ports that will be members in the trunk group.  
2. Follow these steps on the GbESM:  
(a) Define a trunk group.  
>> # /cfg/l2/trunk 1  
(Select trunk group 1)  
>> Trunk group 1# add EXT1  
>> Trunk group 1# add EXT2  
>> Trunk group 1# add EXT3  
>> Trunk group 1# ena  
(Add port EXT1 to trunk group 1)  
(Add port EXT2 to trunk group 1)  
(Add port EXT3 to trunk group 1)  
(Enable trunk group 1)  
(b)Apply and verify the configuration.  
>> Trunk group 1# apply  
(Make your changes active)  
>> Trunk group 1# cur  
(View current trunking configuration)  
Examine the resulting information. If any settings are incorrect, make appropriate changes.  
(c) Save your new configuration changes.  
>> Trunk group 1# save  
(Save for restore after reboot)  
3. Repeat the process on the other switch.  
>> # /cfg/l2/trunk 3  
(Select trunk group 3)  
>> Trunk group 3# add 2  
>> Trunk group 3# add 12  
>> Trunk group 3# add 22  
>> Trunk group 3# ena  
>> Trunk group 3# apply  
>> Trunk group 3# cur  
>> Trunk group 3# save  
(Add port 2 to trunk group 3)  
(Add port 12 to trunk group 3)  
(Add port 22 to trunk group 3)  
(Enable trunk group 3)  
(Make your changes active)  
(View current trunking configuration)  
(Save for restore after reboot)  
Trunk group 1 (on the GbESM) is now connected to trunk group 3 (on Alteon Application  
Switch).  
NOTE In this example, a GbE Switch Module and an application switch are used. If a third-  
party device supporting link aggregation is used (such as Cisco routers and switches with  
EtherChannel technology or Sun's Quad Fast Ethernet Adapter), trunk groups on the third-  
party device should be configured manually. Connection problems could arise when using  
automatic trunk group negotiation on the third-party device.  
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4. Examine the trunking information on each switch.  
>> /info/l2/trunk  
(View trunking information)  
Information about each port in each configured trunk group is displayed. Make sure that trunk  
groups consist of the expected ports and that each port is in the expected state.  
The following restrictions apply:  
Any physical switch port can belong to only one trunk group.  
Up to six ports can belong to the same trunk group.  
Best performance is achieved when all ports in any given trunk group are configured for  
the same speed.  
Trunking from third-party devices must comply with Cisco® EtherChannel® technology.  
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Configurable Trunk Hash Algorithm  
This feature allows you to configure the particular parameters for the GbESM Trunk Hash  
algorithm instead of having to utilize the defaults. You can configure new default behavior for  
Layer 2 traffic and Layer 3 traffic using the CLI menu cfg/l2/thash. You can select a  
minimum of one or a maximum of two parameters to create one of the following configura-  
tions:  
Source IP (SIP)  
Destination IP (DIP)  
Source MAC (SMAC)  
Destination MAC (DMAC)  
Source IP (SIP) + Destination IP (DIP)  
Source MAC (SMAC) + Destination MAC (DMAC)  
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Link Aggregation Control Protocol  
Link Aggregation Control Protocol (LACP) is an IEEE 802.3ad standard for grouping several  
physical ports into one logical port (known as a dynamic trunk group or Link Aggregation  
group) with any device that supports the standard. Please refer to IEEE 802.3ad-2002 for a full  
description of the standard.  
The 802.3ad standard allows standard Ethernet links to form a single Layer 2 link using the  
Link Aggregation Control Protocol (LACP). Link aggregation is a method of grouping physi-  
cal link segments of the same media type and speed in full duplex, and treating them as if they  
were part of a single, logical link segment. If a link in a LACP trunk group fails, traffic is reas-  
signed dynamically to the remaining link/s of the dynamic trunk group.  
NOTE LACP implementation in Alteon OS does not support the Churn machine, an option  
used to detect if the port is operable within a bounded time period between the actor  
and the partner. Only the Market Responder is implemented, and there is no marker protocol  
generator.  
A port’s Link Aggregation Identifier (LAG ID) determines how the port can be aggregated.  
The Link Aggregation ID (LAG ID) is constructed mainly from the system ID and the port’s  
admin key, as follows:  
System ID is an integer value based on the switch’s MAC address and the system priority  
assigned in the CLI.  
Admin key  
A port’s Admin key is an integer value (1 - 65535) that you can configure in the CLI. Each  
GbESM port that participates in the same LACP trunk group must have the same admin key  
value. The Admin key is local significant, which means the partner switch does not need to use  
the same Admin key value.  
For example, consider two switches, an Actor (the GbESM) and a Partner (another switch), as  
shown in Table 4-1.  
Table 4-1 Actor vs. Partner LACP configuration  
Actor Switch  
Partner Switch 2  
Port EXT1 (admin key = 100)  
Port EXT2 (admin key = 100)  
Port 1 (admin key = 50)  
Port 2 (admin key = 50)  
In the configuration shown in Table 4-1, Actor switch ports EXT1 and EXT2 aggregate to  
form an LACP trunk group with Partner switch ports 1 and 2.  
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LACP automatically determines which member links can be aggregated and then aggregates  
them. It provides for the controlled addition and removal of physical links for the link aggrega-  
tion.  
Each port in the GbESM can have one of the following LACP modes.  
off (default)  
The user can configure this port in to a regular static trunk group.  
active  
The port is capable of forming an LACP trunk. This port sends LACPDU packets to part-  
ner system ports.  
passive  
The port is capable of forming an LACP trunk. This port only responds to the LACPDU  
packets sent from an LACP active port.  
Each active LACP port transmits LACP data units (LACPDUs), while each passive LACP  
port listens for LACPDUs. During LACP negotiation, the admin key is exchanged. The LACP  
trunk group is enabled as long as the information matches at both ends of the link. If the admin  
key value changes for a port at either end of the link, that port’s association with the LACP  
trunk group is lost.  
When the system is initialized, all ports by default are in LACP off mode and are assigned  
unique admin keys. To make a group of ports aggregatable, you assign them all the same  
admin key. You must set the port’s LACP mode to active to activate LACP negotiation. You  
can set other port’s LACP mode to passive, to reduce the amount of LACPDU traffic at the ini-  
tial trunk-forming stage.  
Use the /info/l2/trunkcommand or the /info/l2/lacp/dumpcommand to check  
whether the ports are trunked.  
NOTE If you configure LACP on ports with 802.1x network access control, make sure the  
ports on both sides of the connection are properly configured for both LACP and 802.1x.  
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Configuring LACP  
Use the following procedure to configure LACP for port EXT1 and port EXT2 to participate in  
link aggregation.  
1. Set the LACP mode on port EXT1.  
>> # /cfg/l2/lacp/port EXT1  
(Select port EXT1)  
>> LACP port EXT1# mode active  
(Set port EXT1 to LACP active mode)  
2. Define the admin key on port EXT1. Only ports with the same admin key can form a  
LACP trunk group.  
>> LACP port EXT1# adminkey 100  
(Set port EXT1 adminkey to 100)  
Current LACP port adminkey:  
17  
New pending LACP port adminkey: 100  
3. Set the LACP mode on port EXT2.  
>> # /cfg/l2/lacp/port EXT2  
(Select port EXT2)  
>> LACP port EXT2# mode active  
(Set port EXT2 to LACP active mode)  
4. Define the admin key on port EXT2.  
>> LACP port EXT2# adminkey 100  
(Set port EXT2 adminkey to 100)  
Current LACP port adminkey:  
18  
New pending LACP port adminkey: 100  
5. Apply and verify the configuration.  
>> LACP port EXT2# apply  
(Make your changes active)  
>> LACP port EXT2# cur  
(View current trunking configuration)  
6. Save your new configuration changes.  
>> LACP port EXT2# save  
(Save for restore after reboot)  
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CHAPTER 5  
Spanning Tree Group  
so that a switch uses only the most efficient path. The following topics are discussed in this  
chapter:  
“Bridge Protocol Data Units (BPDUs)” on page 107  
“Multiple Spanning Trees” on page 110  
“Port Fast Forwarding” on page 115  
“Fast Uplink Convergence” on page 116  
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Overview  
Spanning Tree Group (STG) detects and eliminates logical loops in a bridged or switched net-  
work. When multiple paths exist, Spanning Tree configures the network so that a switch uses  
only the most efficient path. If that path fails, Spanning Tree automatically sets up another  
active path on the network to sustain network operations.  
GbESM supports IEEE 802.1d Spanning Tree Protocol. It is compatible with PVST+ by con-  
figuring each STP Group in different STP instances.  
NOTE The GbESM also supports IEEE 802.1w Rapid Spanning Tree Protocol, and  
IEEE 802.1s Multiple Spanning Tree Protocol. For more information, see Chapter 6,  
“Rapid Spanning Tree Protocol/Multiple Spanning Tree Protocol.”  
The relationship between port, trunk groups, VLANs, and Spanning Trees is shown in  
Table 5-1.  
Table 5-1 Ports, Trunk Groups, and VLANs  
Switch Element  
Belongs to  
Port  
Trunk group  
or  
One or more VLANs  
Trunk group  
One or more VLANs  
VLAN (non-default)  
One Spanning Tree group  
NOTE Due to Spanning Tree’s sequence of listening, learning, and forwarding or blocking,  
lengthy delays may occur.  
You can use Port Fast Forwarding (/cfg/port x/fastfwd/ena) to permit a port that  
participates in Spanning Tree to bypass the Listening and Learning states and enter directly  
into the Forwarding state. While in the Forwarding state, the port listens to the BPDUs to learn  
if there is a loop and, if dictated by normal STG behavior (following priorities, and so on), the  
port transitions into the Blocking state. This feature permits the GbE Switch Module to inter-  
operate well within Rapid Spanning Tree networks.  
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Bridge Protocol Data Units (BPDUs)  
To create a Spanning Tree, the switch generates a configuration Bridge Protocol Data Unit  
(BPDU), which it then forwards out of its ports. All switches in the Layer 2 network participat-  
ing in the Spanning Tree gather information about other switches in the network through an  
exchange of BPDUs.  
A BPDU is a 64-byte packet that is sent out at a configurable interval, which is typically set for  
two seconds. The BPDU is used to establish a path, much like a “hello” packet in IP routing.  
BPDUs contain information about the transmitting bridge and its ports, including bridge and  
MAC addresses, bridge priority, port priority, and path cost. If the ports are tagged, each port  
sends out a special BPDU containing the tagged information.  
The generic action of a switch on receiving a BPDU is to compare the received BPDU to its  
own BPDU that it will transmit. If the received BPDU is better than its own BPDU, it will  
replace its BPDU with the received BPDU. Then, the switch adds its own bridge ID number  
and increments the path cost of the BPDU. The switch uses this information to block any nec-  
essary ports.  
Determining the Path for Forwarding BPDUs  
When determining which port to use for forwarding and which port to block, the GbE Switch  
Module uses information in the BPDU, including each bridge priority ID. A technique based  
on the “lowest root cost” is then computed to determine the most efficient path for forwarding.  
Bridge Priority  
The bridge priority parameter controls which bridge on the network is the STG root bridge. To  
make one switch the root bridge, configure the bridge priority lower than all other switches and  
bridges on your network. The lower the value, the higher the bridge priority. Use the following  
command to configure the bridge priority:  
/cfg/l2/stg x/brg/prio  
Port Priority  
The port priority helps determine which bridge port becomes the designated port. In a network  
topology that has multiple bridge ports connected to a single segment, the port with the lowest  
port priority becomes the designated port for the segment. Use the following command to con-  
figure the port priority:  
/cfg/l2/stg x/port x/prio  
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Port Path Cost  
The port path cost assigns lower values to high-bandwidth ports, such as Gigabit Ethernet, to  
encourage their use. The cost of a port also depends on whether the port operates at full-duplex  
(lower cost) or half-duplex (higher cost). For example, if a 100-Mbps (Fast Ethernet) link has a  
“cost” of 10 in half-duplex mode, it will have a cost of 5 in full-duplex mode. The objective is  
to use the fastest links so that the route with the lowest cost is chosen. A value of 0 indicates  
that the default cost will be computed for an auto-negotiated link speed.  
Spanning Tree Group configuration guidelines  
This section provides important information on configuring Spanning Tree Groups (STGs):  
Adding a VLAN to a Spanning Tree Group  
If no VLANs exist beyond the default VLAN 1 see “Creating a VLAN” on page 108 for  
information on adding ports to VLANs.  
Add the VLAN to the STG using the /cfg/l2/stg<stg-#>/add <vlan-number>  
command.  
NOTE To ensure proper operation with switches that use Cisco Per VLAN Spanning  
Tree (PVST+), you must either create a separate STG for each VLAN, or  
manually add all associated VLANs into a single STG.  
Creating a VLAN  
When you create a VLAN, that VLAN automatically belongs to STG 1, the default STG. If you  
want the VLAN in another STG, you must move the VLAN by assigning it to another STG.  
Move a newly created VLAN to an existing STG by following this order:  
Create the VLAN  
Add the VLAN to an existing STG  
VLANs must be contained within a single STG; a VLAN cannot span multiple STGs. By  
confining VLANs within a single STG, you avoid problems with spanning tree blocking  
ports and causing a loss of connectivity within the VLAN. When a VLAN spans multiple  
switches, it is recommended that the VLAN remain within the same Spanning Tree Group  
(have the same STG ID) across all the switches.  
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If ports are tagged, all trunked ports can belong to multiple STGs.  
A port that is not a member of any VLAN cannot be added to any STG. The port must be  
added to a VLAN, and that VLAN added to the desired STG.  
Rules for VLAN Tagged ports  
Tagged ports can belong to more than one STG, but untagged ports can belong to only one  
STG.  
When a tagged port belongs to more than one STG, the egress BPDUs are tagged to distin-  
guish the BPDUs of one STG from those of another STG.  
An untagged port cannot span multiple STGs.  
Adding and removing ports from STGs  
When you add a port to a VLAN that belongs to an STG, the port is also added to the STG.  
However, if the port you are adding is an untagged port and is already a member of an  
STG, that port will not be added to an additional STG because an untagged port cannot  
belong to more that one STG.  
For example, assume that VLAN 1 belongs to STG 1. You add an untagged port, port 1,  
that does not belong to any STG to VLAN 1, and port 1 will become part of STG 1.  
If you add untagged port 5 (which is a member to STG 2) to STG 1, the switch will  
prompt you to change the PVID from 2 to 1:  
"Port 5 is an UNTAGGED port and its current PVID is 2.  
Confirm changing PVID from 2 to 1 [y/n]:" y  
When you remove a port from VLAN that belongs to an STG, that port will also be  
removed from the STG. However, if that port belongs to another VLAN in the same STG,  
the port remains in the STG.  
As an example, assume that port 1 belongs to VLAN 1, and VLAN 1 belongs to STG 1.  
When you remove port 1 from VLAN 1, port 1 is also removed from STG 1.  
However, if port 1 belongs to both VLAN 1 and VLAN 2 and both VLANs belong to  
STG 1, removing port 1 from VLAN 1 does not remove port 1 from STG 1 because  
VLAN 2 is still a member of STG 1.  
An STG cannot be deleted, only disabled. If you disable the STG while it still contains  
VLAN members, Spanning Tree will be off on all ports belonging to that VLAN.  
The relationship between port, trunk groups, VLANs, and Spanning Trees is shown in  
Table 5-1.  
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Multiple Spanning Trees  
Each GbE Switch Module supports a maximum of 128 Spanning Tree Groups (STGs). Multi-  
ple STGs provide multiple data paths, which can be used for load-balancing and redundancy.  
You enable load balancing between two GbE Switch Modules using multiple STGs by config-  
uring each path with a different VLAN and then assigning each VLAN to a separate STG. Each  
STG is independent. Each STG sends its own Bridge Protocol Data Units (BPDUs), and each  
STG must be independently configured.  
The STG, or bridge group, forms a loop-free topology that includes one or more virtual LANs  
(VLANs). The switch supports 128 STGs running simultaneously. The default STG 1 may  
contain an unlimited number of VLANs. All other STGs 2-128 may contain only one VLAN  
each.  
Default Spanning Tree configuration  
In the default configuration, a single STG with the ID of 1 includes all non-management ports  
on the switch. It is called the default STG. Although ports can be added to or deleted from the  
default STG, the default STG (STG 1) itself cannot be deleted from the system.  
All other STGs, except the default STG 1 and the management STG 127 and STG 128, are  
empty and VLANs must be added by the user. However, you cannot assign ports directly to  
an STG. Add ports to a VLAN and add the VLAN to the STG. The default configuration of  
management STG 127 contains VLAN 4094 and port EXT7. The default configuration of  
management STG 128 contains VLAN 4095 and internal management ports MGT1 and  
MGT2.  
Each STG is enabled by default, and assigned an ID number from 2 to 126. By default, the  
spanning tree on the management ports (MGT1, MGT2, and EXT7) is turned off in both STP/  
PVST+ mode and in MSTP/RSTP mode.  
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Why Do We Need Multiple Spanning Trees?  
Figure 5-1 shows a simple example of why we need multiple Spanning Trees. Two VLANs,  
VLAN 1 and VLAN 100 exist between application switch A and GbE Switch Module B. If  
you have a single Spanning Tree Group, the switches see an apparent loop, and one VLAN  
may become blocked, affecting connectivity, even though no actual loop exists.  
If VLAN 1 and VLAN 100 belong to different Spanning Tree Groups, then the two instances  
of Spanning Tree separate the topology without forming a loop. Both VLANs can forward  
packets between the switches without losing connectivity.  
BladeCenter  
GbE Switch  
Module B  
Figure 5-1 Using Multiple Instances of Spanning Tree Group  
Switch-Centric Spanning Tree Group  
In Figure 5-2 on page 112, VLAN 2 is shared by application switch A and GbE Switch Module  
B on ports 8 and 17 respectively. Application Switch A identifies VLAN 2 in Spanning Tree  
Group 2 and GbE Switch Module B identifies VLAN 2 in Spanning Tree Group 1. Spanning  
Tree Group is switch-centric—it is used to identify the VLANs participating in the Spanning  
Tree Groups. The Spanning Tree Group ID is not transmitted in the BPDU. Each Spanning  
Tree decision is based on the configuration of that switch.  
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17  
18  
Switch B  
BladeCenter  
Figure 5-2 Implementing Multiple Spanning Tree Groups  
VLAN Participation in Spanning Tree Groups  
The VLAN participation for each Spanning Tree Group in Figure 5-2 on page 112 is discussed  
in the following sections:  
VLAN 1 Participation  
If application switch A is the root bridge, then application switch A will transmit the  
BPDU for VLAN 1 on ports 1 and 2. Application switch C receives the BPDU on its  
port 2 and application switch D receives the BPDU on its port 1. Application switch D will  
block port 8 or application switch C will block port 1 depending on the information pro-  
vided in the BPDU.  
VLAN 2 Participation  
Application switch A, the root bridge generates another BPDU for Spanning Tree Group 2  
and forwards it out from port 8. GbE Switch Module B receives this BPDU on its port 17.  
Port 17 on GbE Switch Module B is on VLAN 2, Spanning Tree Group 2. Because switch  
B has no additional ports participating in Spanning Tree Group 1, this BPDU is not for-  
warded to any additional ports and application switch A remains the designated root.  
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VLAN 3 Participation  
For VLAN 3 you can have GbE Switch Module B or application switch C to be the root  
bridge. If switch B is the root bridge for VLAN 3, Spanning Tree Group 2, then switch B  
transmits the BPDU out from port 18. Application switch C receives this BPDU on port 8  
and is identified as participating in VLAN 3, Spanning Tree Group 2. Since application  
switch C has no additional ports participating in Spanning Tree Group 2, this BPDU is not  
forwarded to any additional ports and GbE Switch Module B remains the designated root.  
Configuring Multiple Spanning Tree Groups  
This configuration shows how to configure the three instances of Spanning Tree Groups on the  
switches A, B, C, and D illustrated in Figure 5-2 on page 112.  
By default Spanning Trees 2-126 are empty, and Spanning Tree Group 1 contains all config-  
ured VLANs until individual VLANs are explicitly assigned to other Spanning Tree Groups.  
You can have only one VLAN per Spanning Tree Group except for Spanning Tree Group 1.  
1. Configure the following on application switch A:  
Add port 8 to VLAN 2 and define Spanning Tree Group 2 for VLAN 2.  
>> # /cfg/l2/vlan2  
>> VLAN 2# add 8  
(Select VLAN 2 menu)  
(Add port 8)  
>> VLAN 2# ../stg 2  
>> Spanning Tree Group 2# add 2  
(Select Spanning Tree Group 2)  
(Add VLAN 2)  
VLAN 2 is automatically removed from Spanning Tree Group 1.  
2. Configure the following on GbE Switch Module B:  
Add port 17 to VLAN 2, port 18 to VLAN 3 and define Spanning Tree Group 2 for VLAN 3.  
>> # /cfg/l2/vlan2  
>> VLAN 2# add 17  
(Select VLAN 2 menu)  
(Add port 17)  
>> VLAN 2# ../vlan3  
>> VLAN 3# add 18  
(Select VLAN 3 menu)  
(Add port 18)  
>> VLAN 3# ../stg 2  
>> Spanning Tree Group 2# add 3  
(Select Spanning Tree Group 2)  
(Add VLAN 3)  
VLAN 3 is removed from Spanning Tree Group 1 and, by default, VLAN 2 remains in  
Spanning Tree Group 1.  
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NOTE Each instance of Spanning Tree Group is enabled by default.  
3. Configure the following on application switch C:  
Add port 8 to VLAN 3 and define Spanning Tree Group 3 for VLAN 3.  
>> # /cfg/l2/vlan3  
(Select VLAN 3 menu)  
>> VLAN 3# add 8  
(Add port 8)  
>> VLAN 3# ../stg 2  
>> Spanning Tree Group 2# add 3  
(Select Spanning Tree Group 2)  
(Add VLAN 3)  
VLAN 3 is automatically removed from Spanning Tree Group 1 and by default VLAN 2  
remains in Spanning Tree Group 1.  
NOTE Application Switch D does not require any special configuration for multiple Spanning  
Trees, because it is configured for the default Spanning Tree Group (STG 1) only.  
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Port Fast Forwarding  
Port Fast Forwarding permits a port that participates in Spanning Tree to bypass the Listening  
and Learning states and enter directly into the Forwarding state. While in the Forwarding state,  
the port listens to the BPDUs to learn if there is a loop and, if dictated by normal STG behavior  
(following priorities, etc.), the port transitions into the Blocking state.  
This feature permits the GbE Switch Module to interoperate well within Rapid Spanning Tree  
(RSTP) networks.  
Configuring Port Fast Forwarding  
Use the following CLI commands to enable Port Fast Forwarding on an external port.  
>> # /cfg/port ext1  
>> Port EXT1# fastfwd ena  
>> Port EXT1# apply  
>> Port EXT1# save  
(Select port EXT 1)  
(Enable Port Fast Forwarding)  
(Make your changes active)  
(Save for restore after reboot)  
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Fast Uplink Convergence  
Fast Uplink Convergence enables the GbESM to quickly recover from the failure of the pri-  
mary link or trunk group in a Layer 2 network using Spanning Tree Protocol. Normal recovery  
can take as long as 50 seconds, while the backup link transitions from Blocking to Listening to  
Learning and then Forwarding states. With Fast Uplink Convergence enabled, the GbESM  
immediately places the secondary path into Forwarding state, and sends multicasts of  
addresses in the forwarding database (FDB) and ARP table over the secondary link so that  
upstream switches can learn the new path.  
Configuration Guidelines  
When you enable Fast Uplink Convergence, Alteon OS automatically makes the following  
configuration changes:  
Sets the bridge priority to 65535 so that it does not become the root switch.  
Increases the cost of all of the external ports by 3000, across all VLANs and Spanning  
Tree Groups. This ensures that traffic never flows through the GbESM to get to another  
switch unless there is no other path.  
These changes are reversed if the feature is disabled.  
Configuring Fast Uplink Convergence  
Use the following CLI commands to enable Fast Uplink Convergence on external ports.  
>> # /cfg/l2/upfast ena  
>> Layer 2# apply  
>> Layer 2# save  
(Enable Fast Uplink convergence)  
(Make your changes active)  
(Save for restore after reboot)  
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CHAPTER 6  
Rapid Spanning Tree Protocol/Multiple  
Spanning Tree Protocol  
IEEE 802.1w Rapid Spanning Tree Protocol enhances the Spanning Tree Protocol to provide  
rapid convergence on Spanning Tree Group 1. IEEE 802.1s Multiple Spanning Tree Protocol  
extends the Rapid Spanning Tree Protocol, to provide both rapid convergence and load balanc-  
ing in a VLAN environment.  
The following topics are discussed in this chapter:  
“MSTP Region” on page 121  
“Common Internal Spanning Tree” on page 121  
“MSTP Configuration Guidelines” on page 122  
“MSTP Configuration Example” on page 122  
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Rapid Spanning Tree Protocol  
Rapid Spanning Tree Protocol (RSTP) provides rapid convergence of the spanning tree and  
provides for fast re-configuration critical for networks carrying delay-sensitive traffic such as  
voice and video. RSTP significantly reduces the time to reconfigure the active topology of the  
network when changes occur to the physical topology or its configuration parameters. RSTP  
reduces the bridged-LAN topology to a single Spanning Tree.  
For more information about Spanning Tree Protocol, see Chapter 5, “Spanning Tree Group.”  
RSTP parameters are configured in Spanning Tree Group 1. STP Groups 2-128 do not apply to  
RSTP, and must be cleared. There are new STP parameters to support RSTP, and some values  
to existing parameters are different.  
RSTP is compatible with devices that run 802.1d Spanning Tree Protocol. If the switch detects  
802.1d BPDUs, it responds with 802.1d-compatible data units. RSTP is not compatible with  
Per VLAN Spanning Tree (PVST+) protocol.  
Port State Changes  
The port state controls the forwarding and learning processes of Spanning Tree. In RSTP, the  
port state has been consolidated to the following: discarding, learning, and forwarding. Table 3  
compares the port states between 802.1d Spanning Tree and 802.1w Rapid Spanning Trees.  
Table 3 RSTP vs. STP Port states  
Operational status  
Enabled  
STP Port State  
Blocking  
RSTP Port State  
Discarding  
Discarding  
Learning  
Enabled  
Listening  
Enabled  
Learning  
Enabled  
Forwarding  
Disabled  
Forwarding  
Discarding  
Disabled  
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Port Type and Link Type  
Spanning Tree configuration includes the following parameters to support  
RSTP and MSTP: edge port and link type. Although these parameters are configured for  
Spanning Tree Groups 1-128 (/cfg/l2/stg x/port x), they only take effect when  
RSTP/MSTP is turned on.  
Edge Port  
A port that does not connect to a bridge is called an edge port. Edge ports generally connect to  
a server, therefore, ports INT1-INT14 should have edgeenabled. Edge ports can start for-  
warding as soon as the link is up.  
Edge ports do not take part in Spanning Tree, and should not receive BPDUs. If a port with  
edgeenabled does receive a BPDU, it begins STP processing only if it is connected to a span-  
ning tree bridge. If it is connected to a host, the edge port ignores BPDUs.  
Link Type  
The link type determines how the port behaves in regard to Rapid Spanning Tree. The link type  
corresponds to the duplex mode of the port. A full-duplex link is point-to-point (p2p), while a  
half-duplex link should be configured as shared. If you select autoas the link type, the port  
dynamically configures the link type.  
RSTP Configuration Guidelines  
This section provides important information about configuring Rapid Spanning Tree Groups:  
When RSTP is turned on, STP parameters apply only to STP Group 1.  
When RSTP is turned on, STG 2-126 are turned off.  
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RSTP Configuration Example  
This section provides steps to configure Rapid Spanning Tree on the GbE Switch Module,  
using the Command-Line Interface (CLI).  
Configure Rapid Spanning Tree  
1. Configure port and VLAN membership on the switch.  
2. Disable and clear STP groups 2 through 126.  
>> /cfg/l2/stg 2  
>> Spanning Tree Group 2# clear  
>> Spanning Tree Group 2# off  
(Select Spanning Tree Group 2)  
(Clear STP Group 2 parameters)  
(Turn off STP Group 2)  
3. Set the Spanning Tree mode to Rapid Spanning Tree.  
>> /cfg/l2/mrst  
>> Multiple Spanning Tree# mode rstp  
>> Multiple Spanning Tree# on  
(Select Multiple Spanning Tree menu)  
(Set mode to Rapid Spanning Tree)  
(Turn Rapid Spanning Tree on)  
4. Configure STP Group 1 parameters.  
>> /cfg/l2/stg 1  
>> Spanning Tree Group 1# add 2  
(Select Spanning Tree Protocol menu)  
(Add VLAN 2 STP Group 1)  
>> Spanning Tree Group 1# apply  
(Apply the configurations)  
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Multiple Spanning Tree Protocol  
IEEE 802.1s Multiple Spanning Tree extends the IEEE 802.1w Rapid Spanning Tree Protocol  
through multiple Spanning Tree Groups. MSTP maintains up to 32 spanning-tree instances,  
that correspond to STP Groups 1-32.  
For more information about Spanning Tree Protocol, see Chapter 5, “Spanning Tree Group.”  
In Multiple Spanning Tree Protocol (MSTP), several VLANs can be mapped to each Span-  
ning-Tree instance. Each Spanning-Tree instance is independent of other instances. MSTP  
allows frames assigned to different VLANs to follow separate paths, each path based on an  
independent Spanning-Tree instance. This approach provides multiple forwarding paths for  
data traffic, enabling load-balancing, and reducing the number of Spanning-Tree instances  
required to support a large number of VLANs.  
By default, the spanning tree on the management ports is turned off in both STP/PVST+ mode  
and in MSTP/RSTP mode.  
MSTP Region  
A group of interconnected bridges that share the same attributes is called an MST region. Each  
bridge within the region must share the following attributes:  
Alphanumeric name  
Revision number  
VLAN-to STG mapping scheme  
MSTP provides rapid re-configuration, scalability and control due to the support of regions,  
and multiple Spanning-Tree instances support within each region.  
Common Internal Spanning Tree  
The Common Internal Spanning Tree (CIST) provides a common form of Spanning Tree Pro-  
tocol, with one Spanning-Tree instance that can be used throughout the MSTP region. CIST  
allows the switch to interoperate with legacy equipment, including devices that run IEEE  
802.1d (STP).  
CIST allows the MSTP region to act as a virtual bridge to other bridges outside of the region,  
and provides a single Spanning-Tree instance to interact with them.  
CIST port configuration includes Hello time, Edge port enable/disable, and Link Type. These  
parameters do not affect Spanning Tree Groups 1-128. They apply only when the CIST is used.  
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MSTP Configuration Guidelines  
This section provides important information about configuring Multiple Spanning Tree  
Groups:  
When you enable MSTP, you must configure the Region Name, and a default version  
number of 1 is configured automatically.  
Each bridge in the region must have the same name, version number, and VLAN mapping.  
MSTP Configuration Example  
This section provides steps to configure Multiple Spanning Tree Protocol on the GbE Switch  
Module, using the Command-Line Interface (CLI).  
Configure Multiple Spanning Tree Protocol  
1. Configure port and VLAN membership on the switch.  
2. Set the mode to Multiple Spanning Tree, and configure MSTP region parameters.  
>> /cfg/l2/mrst  
(Select Multiple Spanning Tree menu)  
(Set mode to Multiple Spanning Trees)  
(Turn Multiple Spanning Trees on)  
(Define the Region name)  
>> Multiple Spanning Tree# mode mstp  
>> Multiple Spanning Tree# on  
>> Multiple Spanning Tree# name xxxxxx  
3. Assign VLANs to Spanning Tree Groups.  
>> /cfg/l2/stg 2  
>> Spanning Tree Group 2# add 2  
(Select Spanning Tree Group 2)  
(Add VLAN 2)  
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CHAPTER 7  
Quality of Service  
Quality of Service features allow you to allocate network resources to mission-critical applica-  
tions at the expense of applications that are less sensitive to such factors as time delays or net-  
work congestion. You can configure your network to prioritize specific types of traffic,  
“Overview” on page 124  
“Using ACL Filters” on page 126  
“Using DSCP Values to Provide QoS” on page 134  
“Using 802.1p Priorities to Provide QoS” on page 139  
“Queuing and Scheduling” on page 140  
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Overview  
QoS helps you allocate guaranteed bandwidth to the critical applications, and limit bandwidth  
for less critical applications. Applications such as video and voice must have a certain amount  
of bandwidth to work correctly; using QoS, you can provide that bandwidth when necessary.  
Also, you can put a high priority on applications that are sensitive to timing out or cannot toler-  
ate delay by assigning that traffic to a high-priority queue.  
By assigning QoS levels to traffic flows on your network, you can ensure that network  
resources are allocated where they are needed most. QoS features allow you to prioritize net-  
work traffic, thereby providing better service for selected applications.  
Figure 7-1 shows the basic QoS model used by the GbESM.  
Ingress Ports  
Meter  
Traffic  
Perform  
Actions  
Queue and  
Schedule  
Egress  
Classify  
Packets  
ACL  
Filter  
ACL  
Meter  
Drop/Pass/  
Re-Mark  
COS  
Queue  
Figure 7-1 QoS Model  
The GbESM uses the Differentiated Services (DiffServ) architecture to provide QoS functions.  
DiffServ is described in IETF RFCs 2474 and 2475.  
With DiffServ, you can establish policies to direct traffic. A policy is a traffic-controlling  
mechanism that monitors the characteristics of the traffic, (for example, its source, destination,  
and protocol) and performs a controlling action on the traffic when certain characteristics are  
matched.  
The GbESM can classify traffic by reading the DiffServ Code Point (DSCP) or IEEE 802.1p  
priority value, or by using filters to match specific criteria. When network traffic attributes  
match those specified in a traffic pattern, the policy instructs the GbESM to perform specified  
actions on each packet that passes through it. The packets are assigned to different Class of  
Service (COS) queues and scheduled for transmission.  
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The basic GbESM QoS model works as follows:  
Classify traffic:  
Read DSCP  
Read 802.1p Priority  
Match ACL filter parameters  
Meter traffic:  
Define bandwidth and burst parameters  
Select actions to perform on in-profile and out-of-profile traffic  
Perform actions:  
Drop packets  
Pass packets  
Mark DSCP or 802.1p Priority  
Set COS queue (with or without re-marking)  
Queue and schedule traffic:  
Place packets in one of two COS queues  
Schedule transmission based on the COS queue weight  
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Using ACL Filters  
Access Control Lists are filters that allow you to classify and segment traffic, so you can pro-  
vide different levels of service to different traffic types. Each filter defines the conditions that  
must match for inclusion in the filter, and also the actions that are performed when a match is  
made.  
Summary of packet classifiers  
The GbESM allows you to classify packets based on various parameters, such as:  
Ethernet  
Source MAC address  
Destination MAC address  
VLAN number/mask  
Ethernet type  
Ethernet Priority, which is the IEEE 802.1p Priority  
IPv4  
Source IP address/mask  
Destination address/mask  
Type of Service value  
IP protocol number protocol number or name as shown in Table 7-1:.  
Table 7-1 Well-Known Protocol Types  
Number Protocol Name  
1
2
6
icmp  
igmp  
tcp  
17  
89  
112  
udp  
ospf  
vrrp  
TCP/UDP  
TCP/UDP application source port as shown in Table 7-2 on page 127  
TCP/UDP application destination port as shown in Table 7-2 on page 127  
TCP/UDP flag value as shown in Table 7-3 on page 127  
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Table 7-2 Well-Known Application Ports  
Number TCP/UDP  
Application  
Number TCP/UDP  
Application  
Number  
TCP/UDP  
Application  
20  
21  
22  
23  
25  
37  
42  
43  
53  
69  
70  
ftp-data  
ftp  
ssh  
telnet  
smtp  
time  
name  
whois  
domain  
tftp  
79  
80  
finger  
http  
pop2  
pop3  
sunrpc  
nntp  
179  
194  
220  
389  
443  
520  
554  
bgp  
irc  
imap3  
ldap  
https  
rip  
109  
110  
111  
119  
123  
143  
144  
161  
162  
ntp  
rtsp  
imap  
news  
snmp  
snmptrap  
1645, 1812 Radius  
1813  
1985  
Radius Accounting  
hsrp  
gopher  
Table 7-3 Well-Known TCP flag values  
Flag  
Value  
URG  
ACK  
PSH  
RST  
SYN  
FIN  
0x0020  
0x0010  
0x0008  
0x0004  
0x0002  
0x0001  
Packet Format  
Ethernet format (eth2, SNAP, LLC)  
Ethernet tagging format  
IP format (IPv4, IPv6)  
Egress port packets  
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Summary of ACL Actions  
Actions determine how the traffic is treated. The GbESM QoS actions include the following:  
Pass or Drop  
Re-mark a new DiffServ Code Point (DSCP)  
Re-mark the 802.1p field  
Set the COS queue  
Understanding ACL Precedence  
Each ACL has a unique precedence level, based on its number. When an incoming packet  
matches the highest precedence ACL, the ACL’s configured action takes place. The other  
assigned ACLs also are considered, in order of precedence.  
ACLs are divided into seven major Precedence Groups, as shown in Table 7-4.  
Table 7-4 ACL Precedence Groups  
Precedence Group  
Precedence Group 1  
Precedence Group 2  
Precedence Group 3  
ACLs  
Precedence Level  
ACL 1 - ACL 128  
ACL 129 - ACL 256  
ACL 257 - ACL 384  
Low  
High  
NOTE Precedence Groups are not related to ACL Groups.  
Each Precedence Group has its own precedence level, such that Precedence Group 2 has a  
higher precedence level than Precedence Group 1. Within each Precedence Group, the lowest-  
numbered ACL has the lowest precedence level, and the highest-numbered ACL has the high-  
est precedence level. However, the other ACLs within the Precedence Group have an unspeci-  
fied precedence level, as follows:  
ACL 1 = lowest precedence level within Precedence Group 1  
ACL 2 = unspecified precedence level within Precedence Group 1  
ACL 3 = unspecified precedence level within Precedence Group 1  
...  
ACL 126 = unspecified precedence level within Precedence Group 1  
ACL 127 = unspecified precedence level within Precedence Group 1  
ACL 128 = highest precedence level within Precedence Group 1  
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Using ACL Groups  
Access Control Lists (ACLs) allow you to classify packets according to a particular content in  
the packet header, such as the source address, destination address, source port number, destina-  
tion port number, and others. Packet classifiers identify flows for more processing.  
You can define a traffic profile by compiling a number of ACLs into an ACL Group, and  
assigning the ACL Group to a port.  
ACL Groups are assigned and enabled on a per-port basis. Each ACL can be used by itself or  
in combination with other ACLs or ACL Groups on a given switch port.  
ACLs can be grouped in the following manner:  
Access Control Lists  
Access Control Lists (ACLs) allow you to classify packets according to a particular con-  
tent in the packet header, such as the source address, destination address, source port num-  
ber, destination port number, and others. Packet classifiers identify flows for more  
processing.  
The GbESM supports up to 384 ACLs. Each ACL defines one filter rule. Each filter rule is  
a collection of matching criteria, and can include an action (permit or deny the packet).  
For example:  
ACL 1:  
VLAN = 1  
SIP = 10.10.10.1 (255.255.255.0)  
Action = permit  
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Access Control Groups  
An Access Control Group (ACL Group) is a collection of ACLs. For example:  
ACL Group 1  
ACL 1:  
VLAN = 1  
SIP = 10.10.10.1 (255.255.255.0)  
Action = permit  
ACL 2:  
VLAN = 2  
SIP = 10.10.10.2 (255.255.255.0)  
Action = deny  
ACL 3:  
Priority = 7  
DIP = 10.10.10.3 (255.255.255.0)  
Action = permit  
In the example above, each ACL defines a filter rule. ACL 3 has a higher precedence than  
ACL 1, based on its number.  
Use ACL Groups to create a traffic profile by gathering ACLs into an ACL Group, and  
assigning the ACL Group to a port. The GbESM supports up to 384 ACL Groups.  
ACL Metering and Re-marking  
You can define a profile for the aggregate traffic flowing through the GbESM ports, by config-  
uring a QoS meter (if desired), and assigning ACL Groups to ports. When you add ACL  
Groups to a port, make sure they are ordered correctly in terms of precedence.  
For example, consider two ACL Groups, ACL Group 1 and ACL Group 2. Each contains three  
levels of precedence. If you add ACL Group 1 to a port, then add ACL Group 2 to the port, the  
port’s ACL filters contain a total of six precedence levels. ACL Group 1 has precedence over  
ACL Group 2.  
Each port supports up to seven precedence levels.  
Actions taken by an ACL are called In-Profile actions. You can configure additional In-Profile  
and Out-of-Profile actions on a port. Data traffic can be metered, and re-marked to ensure that  
the traffic flow provides certain levels of service in terms of bandwidth for different types of  
network traffic.  
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Metering  
QoS metering provides different levels of service to data streams through user-configurable  
parameters. A meter is used to measure the traffic stream against a traffic profile, which you  
create. Thus, creating meters yields In-Profile and Out-of-Profile traffic for each ACL, as  
follows:  
In-Profile–If there is no meter configured or if the packet conforms to the meter, the  
packet is classified as In-Profile.  
Out-of-Profile–If a meter is configured and the packet does not conform to the meter  
(exceeds the committed rate or maximum burst rate of the meter), the packet is classified  
as Out-of-Profile.  
Using meters, you set a Committed Rate in Kb/s (1000 bits per second in each Kb/s). All traffic  
within this Committed Rate is In-Profile. Additionally, you set a Maximum Burst Size that  
specifies an allowed data burst larger than the Committed Rate for a brief period. These param-  
eters define the In-Profile traffic.  
Meters keep the sorted packets within certain parameters. You can configure a meter on an  
ACL, and perform actions on metered traffic, such as packet re-marking.  
Re-Marking  
Re-marking allows for the treatment of packets to be reset based on new network specifica-  
tions or desired levels of service. You can configure the ACL to re-mark a packet as follows:  
Change the DSCP value of a packet, used to specify the service level traffic should  
receive.  
Change the 802.1p priority of a packet.  
Viewing ACL Statistics  
ACL statistics display how many packets hit (matched) each ACL. Use ACL statistics to check  
filter performance, and debug the ACL filters.  
You must enable statistics (cfg/acl/acl x/stats ena) for each ACL that you want to  
monitor.  
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ACL Configuration Examples  
Example 1  
Use this configuration to block traffic to a specific host. All traffic that ingresses on port EXT1  
is denied if it is destined for the host at IP address 100.10.1.1  
1. Configure an Access Control List.  
>> Main# cfg/acl/acl 1  
(Define ACL 1)  
>> ACL 1# ipv4/dip 100.10.1.1  
Enter destination IP address mask (default 255.255.255.255):  
>> Filtering IPv4# ..  
>> ACL 1# action deny  
2. Add ACL 1 to port EXT1.  
>> Main# cfg/port ext1/aclqos  
>> Port EXT1 ACL# /add acl 1  
(Select port EXT 1 to assign ACLs)  
(Assign ACL 1 to the port)  
3. Apply and save the configuration.  
>> Port EXT1 ACL# apply  
>> Port EXT1 ACL# save  
Example 2  
Use this configuration to block traffic from a network destined for a specific host address. All  
traffic that ingresses in port EXT2 with source IP from the class 100.10.1.0/24 and destination  
IP 200.20.2.2 is denied.  
1. Configure an Access Control List.  
>> Main# cfg/acl/acl 2  
(Define ACL 2)  
>> ACL 2# ipv4/sip 100.10.1.0 255.255.255.0  
>> Filtering IPv4# ipv4/dip 200.20.2.2 255.255.255.255  
>> Filtering IPv4# ..  
>> ACL 2# action deny  
2. Add ACL 2 to port EXT2.  
>> Main# cfg/port ext2/aclqos  
>> Port EXT2 ACL# /add acl 2  
(Select port EXT2 to assign ACLs)  
(Assign ACL 2 to the port)  
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3. Apply and save the configuration.  
>> Port EXT2 ACL# apply  
>> Port EXT2 ACL# save  
Example 3  
Use this configuration to block traffic from a network that is destined for a specific egress port.  
All traffic that ingresses port EXT1 from the network 100.10.1.0/24 and is destined for port  
INT1 is denied.  
1. Configure an Access Control List.  
>> Main# cfg/acl/acl 3  
>> ACL 3# ipv4/sip 100.10.1.0 255.255.255.0  
>> Filtering IPv4# ..  
(Define ACL 3)  
>> ACL 3# egrport int1  
>> ACL 3# ..  
>> ACL 3# action deny  
2. Add ACL 3 to port EXT1.  
>> Main# cfg/port ext1/aclqos  
>> Port EXT1 ACL# /add acl 3  
(Select port EXT1 to assign ACLs)  
(Assign ACL 3 to the port)  
3. Apply and save the configuration.  
>> Port EXT2 ACL# apply  
>> Port EXT2 ACL# save  
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Using DSCP Values to Provide QoS  
The six most significant bits in the TOS byte of the IP header are defined as DiffServ Code  
Points (DSCP). Packets are marked with a certain value depending on the type of treatment the  
packet must receive in the network device. DSCP is a measure of the Quality of Service (QoS)  
level of the packet.  
Differentiated Services Concepts  
To differentiate between traffic flows, packets can be classified by their DSCP value. The Dif-  
ferentiated Services (DS) field in the IP header is an octet, and the first six bits, called the DS  
Code Point (DSCP), can provide QoS functions. Each packet carries its own QoS state in the  
DSCP. There are 64 possible DSCP values (0-63).  
Version  
Length  
ID  
Offset TTL Proto FCS  
SIP  
DIP  
Length  
Data  
ToS  
unused  
Differentiated Services Code Point (DSCP)  
7
6
5
4
3
2
1
0
Figure 7-2 Layer 3 IPv4 packet  
The GbESM can perform the following actions to the DSCP:  
Read the DSCP value of ingress packets  
Re-mark the DSCP value to a new value  
Map the DSCP value to an 802.1p priority  
Once the DSCP value is marked, the GbESM can use it to direct traffic prioritization.  
Per Hop Behavior  
The DSCP value determines the Per Hop Behavior (PHB) of each packet. The PHB is the for-  
warding treatment given to packets at each hop. QoS policies are built by applying a set of  
rules to packets, based on the DSCP value, as they hop through the network.  
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The GbESM default settings are based on the following standard PHBs, as defined in the IEEE  
standards:  
Expedited Forwarding (EF)—This PHB has the highest egress priority and lowest drop  
precedence level. EF traffic is forwarded ahead of all other traffic. EF PHB is described in  
RFC 2598.  
Assured Forwarding (AF)—This PHB contains four service levels, each with a different  
drop precedence, as shown below. Routers use drop precedence to determine which  
packets to discard last when the network becomes congested. AF PHB is described in  
RFC 2597.  
Drop  
Class 1  
Class 2  
Class 3  
Class 4  
Precedence  
Low  
AF11 (DSCP 10) AF21 (DSCP 18) AF31 (DSCP 26) AF41 (DSCP 34)  
AF12 (DSCP 12) AF22 (DSCP 20) AF32 (DSCP 28) AF42 (DSCP 36)  
AF13 (DSCP 14) AF23 (DSCP 22) AF33 (DSCP 30) AF43 (DSCP 38)  
Medium  
High  
Class Selector (CS)—This PHB has eight priority classes, with CS7 representing the high-  
est priority, and CS0 representing the lowest priority, as shown below. CS PHB is  
described in RFC 2474.  
Priority  
Class Selector  
CS7  
DSCP  
56  
48  
40  
32  
24  
16  
8
Highest  
CS6  
CS5  
CS4  
CS3  
CS2  
CS1  
Lowest  
CS0  
0
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QoS Levels  
Table 7-5 shows the default service levels provided by the GbESM, listed from highest to  
lowest importance:  
Table 7-5 Default QoS Service Levels  
Service Level  
Critical  
Default PHB  
802.1p Priority  
CS7  
7
6
5
4
3
2
1
0
Network Control  
Premium  
Platinum  
Gold  
CS6  
EF, CS5  
AF41, AF42, AF43, CS4  
AF31, AF32, AF33, CS3  
AF21, AF22, AF23, CS2  
AF11, AF12, AF13, CS1  
DF, CS0  
Silver  
Bronze  
Standard  
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DSCP Re-marking and Mapping  
The GbESM can re-mark the DSCP value of ingress packets to a new value, and set the  
802.1p priority value, based on the DSCP value. You can view the default settings by using  
the cfg/qos/dscp/curcommand, as shown below.  
>> DSCP Remark# cur  
Current DSCP Remarking Configuration: OFF  
DSCP  
New DSCP New 802.1p Prio  
-------- -------- ---------------  
0
1
0
1
0
0
...  
51  
52  
53  
54  
55  
56  
57  
58  
59  
60  
61  
62  
63  
51  
52  
53  
54  
55  
56  
57  
58  
59  
60  
61  
62  
63  
0
0
0
0
0
7
0
0
0
0
0
0
0
Use the cfg/qos/dscp/oncommand to turn on DSCP re-marking globally. Then you must  
enable DSCP re-marking (cfg/port x/dscpmrk/ena) on any port that you wish to per-  
form this function.  
NOTE If an ACL meter is configured for DSCP re-marking, the meter function takes prece-  
dence over QoS re-marking.  
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DSCP Re-marking Configuration Example  
1. Turn DSCP re-marking on globally, and define the DSCP-DSCP-802.1p mapping. You  
can use the default mapping, as shown in the cfg/qos/dscp/curcommand output.  
>> Main# cfg/qos/dscp/on  
>> DSCP Remark# dscp 8  
(Turn on DSCP re-marking)  
(Define DSCP re-marking)  
Current DSCP remark (for DSCP 8): 8  
Enter new DSCP remark (for DSCP 8) [0-63]: 10  
>> DSCP Remark# prio  
(Define DSCP-to-802.1p mapping)  
Enter DSCP [0-63]: 10  
Current prio (for DSCP 10): 1  
Enter new prio (for DSCP 10) [0-7]: 2  
>> DSCP Remark# apply  
2. Enable DSCP re-marking on a port.  
>> Main# cfg/port EXT1  
(Select port)  
>> Port EXT1# dscpmrk ena  
Current DSCP remarking: disabled  
(Enable DSCP re-marking)  
New DSCP remarking:  
enabled  
>> Port EXT1# apply  
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Using 802.1p Priorities to Provide QoS  
Alteon OS provides Quality of Service functions based on the priority bits in a packet’s VLAN  
header. (The priority bits are defined by the 802.1p standard within the IEEE 802.1q VLAN  
header.) The 802.1p bits, if present in the packet, specify the priority that should be given to  
packets during forwarding. Packets with a numerically higher (non-zero) priority are given for-  
warding preference over packets with lower priority bit value.  
The IEEE 802.1p standard uses eight levels of priority (0-7). Priority 7 is assigned to highest  
priority network traffic, such as OSPF or RIP routing table updates, priorities 5-6 are assigned  
to delay-sensitive applications such as voice and video, and lower priorities are assigned to  
standard applications. A value of 0 (zero) indicates a “best effort” traffic prioritization, and this  
is the default when traffic priority has not been configured on your network. The GbESM can  
filter packets based on the 802.1p values, and it can assign or overwrite the 802.1p value in the  
packet.  
DMAC SMAC Tag E Type  
FCS  
SFD  
Data  
Preamble  
Priority  
VLAN Identifier (VID)  
7
6
5
4
3
2
Figure 7-3 Layer 2 802.1q/802.1p VLAN tagged packet  
Ingress packets receive a priority value, as follows:  
1
0
7
6
5
4
3
2
1
0
Tagged packets—GbESM reads the 802.1p priority in the VLAN tag.  
Untagged packets—GbESM tags the packet and assigns an 802.1p priority, based on the  
port’s default priority (/cfg/port x/8021ppri).  
Egress packets are placed in a COS queue based on the priority value, and scheduled for trans-  
mission based on the scheduling weight of the COS queue.  
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802.1p Configuration Example  
1. Configure a port’s default 802.1p priority.  
>> Main# cfg/port EXT1  
>> Port EXT1# 8021ppri  
Current 802.1p priority: 0  
Enter new 802.1p priority [0-7]: 1  
>> Port EXT1# ena  
(Select port)  
(Set ports default 802.1p priority)  
>> Port EXT1# apply  
2. Map the 802.1p priority value to a COS queue and set the COS queue scheduling weight.  
>> Main# cfg/qos/8021p  
(Select 802.1p menu)  
>> 802.1p# priq  
(Set COS queue assignments)  
Enter priority [0-7]: 1  
Current COS queue (for priority 1): 0  
Enter new COS queue (for priority 1) [0-1]: 1  
>> 802.1p# qweight  
(Set COS queue weights)  
Enter COS queue [0-1]: 1  
Current weight (for COS queue 1): 3  
Enter new weight (for COS queue 1) [0-15]: 10  
>> 802.1p# apply  
Queuing and Scheduling  
The GbESM has eight output Class of Service (COS) queues per port, into which each packet  
is placed. Each packet’s 802.1p priority determines its COS queue, except when an ACL action  
sets the COS queue of the packet.  
Each COS queue uses Weighted Round Robin (WRR) scheduling, with user configurable  
weight from 1 to 15. The weight of 0 (zero) indicates strict priority, which might starve the low  
priority queues.  
You can configure the following attributes for COS queues:  
Map 802.1p priority value to a COS queue  
Define the scheduling weight of each COS queue  
Use the 802.1p menu (/cfg/qos/8021p) to configure COS queues.  
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Part 2: IP Routing  
This section discusses Layer 3 switching functions. In addition to switching traffic at near line  
rates, the application switch can perform multi-protocol routing. This section discusses basic  
routing and advanced routing protocols:  
Basic Routing  
Routing Information Protocol (RIP)  
Internet Group Management Protocol (IGMP)  
Border Gateway Protocol (BGP)  
Open Shortest Path First (OSPF)  
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CHAPTER 8  
This chapter provides configuration background and examples for using the GbE Switch Mod-  
ule to perform IP routing functions. The following topics are addressed in this chapter:  
“IP Routing Benefits” on page 144  
“Routing Between IP Subnets” on page 145  
“Example of Subnet Routing” on page 148  
“Dynamic Host Configuration Protocol” on page 152  
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IP Routing Benefits  
The GbE Switch Module uses a combination of configurable IP switch interfaces and IP rout-  
ing options. The switch IP routing capabilities provide the following benefits:  
Connects the server IP subnets to the rest of the backbone network.  
Provides another means to invisibly introduce Jumbo frame technology into the server-  
switched network by automatically fragmenting UDP Jumbo frames when routing to non-  
Jumbo frame VLANs or subnets.  
Provides the ability to route IP traffic between multiple Virtual Local Area Networks  
(VLANs) configured on the switch.  
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Routing Between IP Subnets  
The physical layout of most corporate networks has evolved over time. Classic hub/router  
topologies have given way to faster switched topologies, particularly now that switches are  
increasingly intelligent. GbE Switch Modules are intelligent and fast enough to perform rout-  
ing functions on a par with wire speed Layer 2 switching.  
The combination of faster routing and switching in a single device provides another service—  
it allows you to build versatile topologies that account for legacy configurations.  
For example, consider the following topology migration:  
Internet  
GbE  
Internet  
Switch  
Module  
BladeCenter  
Figure 8-1 The Router Legacy Network  
In this example, a corporate campus has migrated from a router-centric topology to a faster,  
more powerful, switch-based topology. As is often the case, the legacy of network growth and  
redesign has left the system with a mix of illogically distributed subnets.  
This is a situation that switching alone cannot cure. Instead, the router is flooded with cross-  
subnet communication. This compromises efficiency in two ways:  
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Routers can be slower than switches. The cross-subnet side trip from the switch to the  
router and back again adds two hops for the data, slowing throughput considerably.  
Traffic to the router increases, increasing congestion.  
Even if every end-station could be moved to better logical subnets (a daunting task), competi-  
tion for access to common server pools on different subnets still burdens the routers.  
This problem is solved by using GbE Switch Modules with built-in IP routing capabilities.  
Cross-subnet LAN traffic can now be routed within the switches with wire speed Layer 2  
switching performance. This not only eases the load on the router but saves the network  
administrators from reconfiguring each and every end-station with new IP addresses.  
Take a closer look at the BladeCenter’s GbE Switch Module in the following configuration  
example:  
10 Gbps  
Ser ver Su b n et :  
206.30.15.2-254  
IF#3  
IF#2  
IF#4  
GbESM  
IF#1  
10 Gbps  
BladeCenter  
Figure 8-2 Switch-Based Routing Topology  
The GbE Switch Module connects the Gigabit Ethernet and Fast Ethernet trunks from various  
switched subnets throughout one building. Common servers are placed on another subnet  
attached to the switch. A primary and backup router are attached to the switch on yet another  
subnet.  
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Without Layer 3 IP routing on the switch, cross-subnet communication is relayed to the default  
gateway (in this case, the router) for the next level of routing intelligence. The router fills in the  
necessary address information and sends the data back to the switch, which then relays the  
packet to the proper destination subnet using Layer 2 switching.  
With Layer 3 IP routing in place on the GbE Switch Module, routing between different IP sub-  
nets can be accomplished entirely within the switch. This leaves the routers free to handle  
inbound and outbound traffic for this group of subnets.  
To make implementation even easier, UDP Jumbo frame traffic is automatically fragmented to  
regular Ethernet frame sizes when routing to non-Jumbo frame VLANS or subnets. This auto-  
matic frame conversion allows servers to communicate using Jumbo frames, all transparently  
to the user.  
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Example of Subnet Routing  
Prior to configuring, you must be connected to the switch Command Line Interface (CLI) as  
the administrator.  
example, see the Alteon OS Command Reference.  
1. Assign an IP address (or document the existing one) for each router and client worksta-  
tion.  
In the example topology in Figure 8-2 on page 146, the following IP addresses are used:  
Table 8-1 Subnet Routing Example: IP Address Assignments  
Subnet  
Devices  
IP Addresses  
1
2
3
4
Primary and Secondary Default Routers 205.21.17.1 and 205.21.17.2  
First Floor Client Workstations  
Second Floor Client Workstations  
Common Servers  
100.20.10.2-254  
131.15.15.2-254  
206.30.15.2-254  
2. Assign an IP interface for each subnet attached to the switch.  
Since there are four IP subnets connected to the switch, four IP interfaces are needed:  
Table 8-2 Subnet Routing Example: IP Interface Assignments  
Interface  
IF 1  
Devices  
IP Interface Address  
Primary and Secondary Default Routers 205.21.17.3  
IF 2  
First Floor Client Workstations  
Second Floor Client Workstations  
Common Servers  
100.20.10.1  
131.15.15.1  
206.30.15.1  
IF 3  
IF 4  
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IP interfaces are configured using the following commands at the CLI:  
>> # /cfg/l3/if 1  
(Select IP interface 1)  
>> IP Interface 1# addr 205.21.17.3  
>> IP Interface 1# ena  
(Assign IP address for the interface)  
(Enable IP interface 1)  
>> IP Interface 1# ../if 2  
>> IP Interface 2# addr 100.20.10.1  
>> IP Interface 2# ena  
(Select IP interface 2)  
(Assign IP address for the interface)  
(Enable IP interface 2)  
>> IP Interface 2# ../if 3  
>> IP Interface 3# addr 131.15.15.1  
>> IP Interface 3# ena  
(Select IP interface 3)  
(Assign IP address for the interface)  
(Enable IP interface 3)  
>> IP Interface 3# ../if 4  
>> IP Interface 4# addr 206.30.15.1  
>> IP Interface 4# ena  
(Select IP interface 4)  
(Assign IP address for the interface)  
(Enable IP interface 5)  
3. Set each server and workstation’s default gateway to the appropriate switch IP interface  
(the one in the same subnet as the server or workstation).  
4. Configure the default gateways to the routers’ addresses.  
Configuring the default gateways allows the switch to send outbound traffic to the routers:  
>> IP Interface 5# ../gw 1  
>> Default gateway 1# addr 205.21.17.1  
>> Default gateway 1# ena  
>> Default gateway 1# ../gw 2  
>> Default gateway 2# addr 205.21.17.2  
>> Default gateway 2# ena  
(Select primary default gateway)  
(Assign IP address for primary router)  
(Enable primary default gateway)  
(Select secondary default gateway)  
(Assign address for secondary router)  
(Enable secondary default gateway)  
5. Apply and verify the configuration.  
>> Default gateway 2# # apply  
>> Default gateway 2# /cfg/l3/cur  
(Make your changes active)  
(View current IP settings)  
Examine the resulting information. If any settings are incorrect, make the appropriate changes.  
6. Save your new configuration changes.  
>> IP# save  
(Save for restore after reboot)  
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Using VLANs to Segregate Broadcast Domains  
In the previous example, devices that share a common IP network are all in the same broadcast  
domain. If you want to limit the broadcasts on your network, you could use VLANs to create  
distinct broadcast domains. For example, as shown in the following procedure, you could cre-  
ate one VLAN for the client trunks, one for the routers, and one for the servers.  
In this example, you are adding to the previous configuration.  
1. Determine which switch ports and IP interfaces belong to which VLANs.  
The following table adds port and VLAN information:  
Table 8-3 Subnet Routing Example: Optional VLAN Ports  
VLAN Devices  
IP Interface Switch Port VLAN #  
1
2
3
First Floor Client Workstations  
2
3
1
1
4
4
EXT1  
EXT2  
EXT3  
EXT4  
INT5  
INT6  
1
1
2
2
3
3
Second Floor Client Workstations  
Primary Default Router  
Secondary Default Router  
Common Servers 1  
Common Servers 2  
2. Add the switch ports to their respective VLANs.  
The VLANs shown in Table 8-3 are configured as follows:  
>> # /cfg/l2/vlan 1  
>> VLAN 1# add port EXT1  
>> VLAN 1# add port EXT2  
>> VLAN 1# ena  
(Select VLAN 1)  
(Add port for 1st floor to VLAN 1)  
(Add port for 2nd floor to VLAN 1)  
(Enable VLAN 1)  
>> VLAN 1# ../VLAN 2  
>> VLAN 2# add port EXT3  
>> VLAN 2# add port EXT4  
>> VLAN 2# ena  
(Select VLAN 2)  
(Add port for default router 1)  
(Add port for default router 2)  
(Enable VLAN 2)  
>> VLAN 2# ../VLAN 3  
>> VLAN 3# add port INT5  
>> VLAN 3# add port INT6  
>> VLAN 3# ena  
(Add port for default router 3)  
(Select VLAN 3)  
(Select port for common server 1)  
(Enable VLAN 3)  
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Each time you add a port to a VLAN, you may get the following prompt:  
Port 4 is an untagged port and its current PVID is 1.  
Confirm changing PVID from 1 to 2 [y/n]?  
Enter yto set the default Port VLAN ID (PVID) for the port.  
3. Add each IP interface to the appropriate VLAN.  
Now that the ports are separated into three VLANs, the IP interface for each subnet must be  
placed in the appropriate VLAN. From Table 8-3 on page 150, the settings are made as fol-  
lows:  
>> VLAN 3# /cfg/l3/if 1  
>> IP Interface 1# vlan 2  
>> IP Interface 1# ../if 2  
>> IP Interface 2# vlan 1  
>> IP Interface 2# ../if 3  
>> IP Interface 3# vlan 1  
>> IP Interface 3# ../if 4  
>> IP Interface 4# vlan 3  
(Select IP interface 1 for def. routers)  
(Set to VLAN 2)  
(Select IP interface 2 for first floor)  
(Set to VLAN 1)  
(Select IP interface 3 for second floor)  
(Set to VLAN 1)  
(Select IP interface 4 for servers)  
(Set to VLAN 3)  
4. Apply and verify the configuration.  
>> IP Interface 5# apply  
>> IP Interface 5# /info/vlan  
>> Information# port  
(Make your changes active)  
(View current VLAN information)  
(View current port information)  
Examine the resulting information. If any settings are incorrect, make the appropriate changes.  
5. Save your new configuration changes.  
>> Information# save  
(Save for restore after reboot)  
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Dynamic Host Configuration Protocol  
Dynamic Host Configuration Protocol (DHCP) is a transport protocol that provides a frame-  
work for automatically assigning IP addresses and configuration information to other IP hosts  
or clients in a large TCP/IP network. Without DHCP, the IP address must be entered manually  
for each network device. DHCP allows a network administrator to distribute IP addresses from  
a central point and automatically send a new IP address when a device is connected to a differ-  
ent place in the network.  
DHCP is an extension of another network IP management protocol, Bootstrap Protocol  
(BOOTP), with an additional capability of being able to dynamically allocate reusable network  
addresses and configuration parameters for client operation.  
Built on the client/server model, DHCP allows hosts or clients on an IP network to obtain their  
configurations from a DHCP server, thereby reducing network administration. The most sig-  
nificant configuration the client receives from the server is its required IP address; (other  
optional parameters include the “generic” file name to be booted, the address of the default  
gateway, and so forth).  
DHCP relay agent eliminates the need to have DHCP/BOOTP servers on every subnet. It  
allows the administrator to reduce the number of DHCP servers deployed on the network and  
to centralize them. Without the DHCP relay agent, there must be at least one DHCP server  
deployed at each subnet that has hosts needing to perform the DHCP request.  
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DHCP Relay Agent  
DHCP is described in RFC 2131, and the DHCP relay agent supported on GbE Switch Mod-  
ules is described in RFC 1542. DHCP uses UDP as its transport protocol. The client sends  
messages to the server on port 67 and the server sends messages to the client on port 68.  
DHCP defines the methods through which clients can be assigned an IP address for a finite  
lease period and allowing reassignment of the IP address to another client later. Additionally,  
DHCP provides the mechanism for a client to gather other IP configuration parameters it needs  
to operate in the TCP/IP network.  
In the DHCP environment, the GbE Switch Module acts as a relay agent. The DHCP relay fea-  
ture (/cfg/l3/bootp) enables the switch to forward a client request for an IP address to  
two BOOTP servers with IP addresses that have been configured on the switch.  
When a switch receives a UDP broadcast on port 67 from a DHCP client requesting an IP  
address, the switch acts as a proxy for the client, replacing the client source IP (SIP) and desti-  
nation IP (DIP) addresses. The request is then forwarded as a UDP Unicast MAC layer mes-  
sage to two BOOTP servers whose IP addresses are configured on the switch. The servers  
respond as a UDP Unicast message back to the switch, with the default gateway and IP address  
for the client. The destination IP address in the server response represents the interface address  
on the switch that received the client request. This interface address tells the switch on which  
VLAN to send the server response to the client.  
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DHCP Relay Agent Configuration  
To enable the GbE Switch Module to be the BOOTP forwarder, you need to configure the  
DHCP/BOOTP server IP addresses on the switch. You generally configure the IP interface on  
the client side to match the client’s subnet, and configure VLANs to separate client and server  
subnets. The DHCP server knows from which IP subnet the newly allocated IP address should  
come.  
The following figure shows a basic DHCP network example:  
GbESM  
DHCP  
Server  
BladeCenter  
Figure 8-3 DHCP Relay Agent Configuration  
In GbE Switch Module implementation, there is no need for primary or secondary servers. The  
client request is forwarded to the BOOTP servers configured on the switch. The use of two  
servers provide failover redundancy. However, no health checking is supported.  
Use the following commands to configure the switch as a DHCP relay agent:  
>> # /cfg/l3/bootp  
>> Bootstrap Protocol Relay# addr  
>> Bootstrap Protocol Relay# addr2  
>> Bootstrap Protocol Relay# on  
>> Bootstrap Protocol Relay# off  
>> Bootstrap Protocol Relay# cur  
(Set IP address of BOOTP server)  
(Set IP address of 2nd BOOTP server)  
(Globally turn BOOTP relay on)  
(Globally turn BOOTP relay off)  
(Display current configuration)  
Additionally, DHCP Relay functionality can be assigned on a per interface basis. Use the fol-  
lowing command to enable the Relay functionality:  
>> # /cfg/l3/if <interface number>/relay ena  
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CHAPTER 9  
Routing Information Protocol  
In a routed environment, routers communicate with one another to keep track of available  
routes. Routers can learn about available routes dynamically using the Routing Information  
Protocol (RIP). Alteon OS software supports RIP version 1 (RIPv1) and RIP version 2 (RIPv2)  
for exchanging TCP/IP route information with other routers.  
Distance Vector Protocol  
RIP is known as a distance vector protocol. The vector is the network number and next hop,  
and the distance is the cost associated with the network number. RIP identifies network reach-  
ability based on cost, and cost is defined as hop count. One hop is considered to be the distance  
from one switch to the next which is typically 1. This cost or hop count is known as the metric.  
When a switch receives a routing update that contains a new or changed destination network  
entry, the switch adds 1 to the metric value indicated in the update and enters the network in  
the routing table. The IP address of the sender is used as the next hop.  
Stability  
RIP includes a number of other stability features that are common to many routing protocols.  
For example, RIP implements the split horizon and hold-down mechanisms to prevent incor-  
rect routing information from being propagated.  
RIP prevents routing loops from continuing indefinitely by implementing a limit on the num-  
ber of hops allowed in a path from the source to a destination. The maximum number of hops  
in a path is 15. The network destination network is considered unreachable if increasing the  
metric value by 1 causes the metric to be 16 (that is infinity). This limits the maximum diame-  
ter of a RIP network to less than 16 hops.  
RIP is often used in stub networks and in small autonomous systems that do not have many  
redundant paths.  
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Routing Updates  
RIP sends routing-update messages at regular intervals and when the network topology  
changes. Each router “advertises” routing information by sending a routing information update  
every 30 seconds. If a router doesn’t receive an update from another router for 180 seconds,  
those routes provided by that router are declared invalid. After another 120 seconds without  
receiving an update for those routes, the routes are removed from the routing table and respec-  
tive regular updates.  
When a router receives a routing update that includes changes to an entry, it updates its routing  
table to reflect the new route. The metric value for the path is increased by 1, and the sender is  
indicated as the next hop. RIP routers maintain only the best route (the route with the lowest  
metric value) to a destination.  
For more information see The Configuration Menu, Routing Information Protocol Configura-  
tion (/cfg/l3/rip) in the Alteon OS Command Reference.  
RIPv1  
RIP version 1 use broadcast User Datagram Protocol (UDP) data packets for the regular rout-  
ing updates. The main disadvantage is that the routing updates do not carry subnet mask infor-  
mation. Hence, the router cannot determine whether the route is a subnet route or a host route.  
It is of limited usage after the introduction of RIPv2. For more information about  
RIPv1 and RIPv2, refer to RFC 1058 and RFC 2453.  
RIPv2  
RIPv2 is the most popular and preferred configuration for most networks. RIPv2 expands the  
amount of useful information carried in RIP messages and provides a measure of security. For  
a detailed explanation of RIPv2, refer to RFC 1723 and RFC 2453.  
RIPv2 improves efficiency by using multicast UDP (address 224.0.0.9) data packets for regu-  
lar routing updates. Subnet mask information is provided in the routing updates. A security  
option is added for authenticating routing updates, by using a shared password. Alteon OS sup-  
ports using clear password for RIPv2.  
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RIPv2 in RIPv1 compatibility mode  
Alteon OS allows you to configure RIPv2 in RIPv1compatibility mode, for using both RIPv2  
and RIPv1 routers within a network. In this mode, the regular routing updates use broadcast  
UDP data packet to allow RIPv1 routers to receive those packets. With RIPv1 routers as recip-  
ients, the routing updates have to carry natural or host mask. Hence, it is not a recommended  
configuration for most network topologies.  
NOTE When using both RIPv1 and RIPv2 within a network, use a single subnet mask  
throughout the network.  
RIP Features  
Alteon OS provides the following features to support RIPv1 and RIPv2:  
Poison  
Simple split horizon in RIP scheme omits routes learned from one neighbor in updates sent to  
that neighbor. That is the most common configuration used in RIP, that is setting this Poison to  
DISABLE. Split horizon with poisoned reverse includes such routes in updates, but sets their  
metrics to 16. The disadvantage of using this feature is the increase of size in the routing  
updates.  
Triggered updates  
Triggered updates are an attempt to speed up convergence. When Triggered Updates is enabled  
(/cfg/l3/rip/if x/trigg/e), whenever a router changes the metric for a route, it  
sends update messages almost immediately, without waiting for the regular update interval. It  
is recommended to enable Triggered Updates.  
Multicast  
RIPv2 messages use IP multicast address (224.0.0.9) for periodic broadcasts. Multicast RIPv2  
announcements are not processed by RIPv1 routers. IGMP is not needed since these are inter-  
router messages which are not forwarded.  
To configure RIPv2 in RIPv1 compatibility mode, set multicast to disable, and set version  
to both.  
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Default  
The RIP router can listen and supply a default route, usually represented as 0.0.0.0 in the rout-  
ing table. When a router does not have an explicit route to a destination network in its routing  
table, it uses the default route to forward those packets.  
Metric  
The metric field contains a configurable value between 1 and 15 (inclusive) which specifies the  
current metric for the interface. The metric value typically indicates the total number of hops to  
the destination. The metric value of 16 represents an unreachable destination.  
Authentication  
RIPv2 authentication uses plaintext password for authentication. If configured using Authenti-  
cation password, then it is necessary to enter an authentication key value.  
The following method is used to authenticate a RIP message:  
If the router is not configured to authenticate RIPv2 messages, then RIPv1 and unauthenti-  
cated RIPv2 messages are accepted; authenticated RIPv2 messages are discarded.  
If the router is configured to authenticate RIPv2 messages, then RIPv1 messages and  
RIPv2 messages which pass authentication testing are accepted; unauthenticated and  
failed authentication RIPv2 messages are discarded.  
For maximum security, RIPv1 messages are ignored when authentication is enabled  
(cfg/l3/rip/if x/auth/password); otherwise, the routing information from authen-  
ticated messages is propagated by RIPv1 routers in an unauthenticated manner.  
RIP Configuration Example  
NOTE An interface RIP disabled uses all the default values of the RIP, no matter how the  
RIP parameters are configured for that interface. RIP sends out RIP regular updates to include  
an UP interface, but not a DOWN interface.  
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1. Add VLANs for routing interfaces.  
>> Main# cfg/l2/vlan 2/ena  
>> VLAN 2# add ext2  
(Enable VLAN 2)  
(Add port EXT2 to VLAN 2)  
Port EXT2 is an UNTAGGED port and its current PVID is 1.  
Confirm changing PVID from 1 to 2 [y/n]: y  
>> VLAN 2# /cfg/l2/vlan 3/ena  
(Enable VLAN 3)  
>> VLAN 3# add ext3  
(Add port EXT3 to VLAN 3)  
Port EXT3 is an UNTAGGED port and its current PVID is 1.  
Confirm changing PVID from 1 to 3 [y/n]: y  
2. Add IP interfaces to VLANs.  
>> Main# cfg/l3/if 2/ena  
(Enable interface 2)  
>> IP Interface 2# addr 102.1.1.1  
>> IP Interface 2# vlan 2  
>> IP Interface 2# /cfg/l3/if 3/ena  
>> IP Interface 3# addr 103.1.1.1  
>> IP Interface 3# vlan 3  
(Define IP address for interface 2)  
(Add interface 2 to VLAN 2)  
(Enable interface 3)  
(Define IP address for interface 3)  
(Add interface 3 to VLAN 3)  
3. Turn on RIP globally and enable RIP for each interface.  
>> Main# cfg/l3/rip on  
(Turn on RIP globally)  
>> Routing Information Protocol# if 2/ena (Enable RIP on IP interface 2)  
>> RIP Interface 2# ..  
>> Routing Information Protocol# if 3/ena (Enable RIP on IP interface 3)  
>> RIP Interface 3# apply  
(Apply your changes)  
>> RIP Interface 3# save  
(Save the configuration)  
Use the /maint/route/dumpcommand to check the current valid routes in the routing  
table of the switch.  
For those RIP learnt routes within the garbage collection period, that are routes phasing out of  
the routing table with metric 16, use the /info/l3/rip/routescommand. Locally con-  
figured static routes do not appear in the RIP Routes table.  
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CHAPTER 10  
IGMP  
Internet Group Management Protocol (IGMP) is used by IP Multicast routers to learn about the  
existence of host group members on their directly attached subnet (see RFC 2236). The IP  
Multicast routers get this information by broadcasting IGMP Membership Queries and listen-  
ing for IP hosts reporting their host group memberships. This process is used to set up a client/  
server relationship between an IP Multicast source that provides the data streams and the cli-  
ents that want to receive the data.  
The GbESM can perform IGMP Snooping, or act as an IGMP Relay (proxy) device.  
The following topics are discussed in this chapter:  
“IGMP Snooping” on page 162  
“IGMP Relay” on page 165  
“Additional IGMP Features” on page 168  
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IGMP Snooping  
IGMP Snooping allows the switch to forward multicast traffic only to those ports that request  
it. IGMP Snooping prevents multicast traffic from being flooded to all ports. The switch learns  
which server hosts are interested in receiving multicast traffic, and forwards it only to ports  
connected to those servers.  
IGMP Snooping conserves bandwidth. With IGMP Snooping, the switch learns which ports  
are interested in receiving multicast data, and forwards multicast data only to those ports. In  
this way, other ports are not burdened with unwanted multicast traffic.  
The switch can sense IGMP Membership Reports from attached clients and act as a proxy to  
set up a dedicated path between the requesting host and a local IP Multicast router. After the  
pathway is established, the switch blocks the IP Multicast stream from flowing through any  
port that does not connect to a host member, thus conserving bandwidth.  
The client-server path is set up as follows:  
An IP Multicast Router (Mrouter) sends Membership Queries to the switch, which for-  
wards them to all ports in a given VLAN.  
Hosts that want to receive the multicast data stream send Membership Reports to the  
switch, which sends a proxy Membership Report to the Mrouter.  
The switch sets up a path between the Mrouter and the host, and blocks all other ports  
from receiving the multicast.  
Periodically, the Mrouter sends Membership Queries to ensure that the host wants to con-  
tinue receiving the multicast. If a host fails to respond with a Membership Report, the  
Mrouter stops sending the multicast to that path.  
The host can send a Leave Report to the switch, which sends a proxy Leave Report to the  
Mrouter. The multicast path is terminated immediately.  
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IGMP Snooping Configuration Example  
This section provides steps to configure IGMP Snooping on the GbESM, using the Command-  
Line Interface (CLI).  
Configure IGMP Snooping  
1. Configure port and VLAN membership on the switch.  
2. Turn on IGMP.  
>> /cfg/l3/igmp/on  
(Turn on IGMP)  
3. Add VLANs to IGMP Snooping and enable the feature.  
>> /cfg/l3/igmp/snoop  
>> IGMP Snoop# add 1  
>> IGMP Snoop# ena  
(Access IGMP Snoop menu)  
(Add VLAN 1 to IGMP snooping)  
(Enable IGMP Snooping)  
4. Apply and save the configuration.  
>> IGMP Snoop# apply  
>> IGMP Snoop# save  
(Apply the configuration)  
(Save your changes)  
5. View dynamic IGMP information.  
>> /info/l3/igmp  
>> IGMP Multicast Group# dump  
(Select IGMP information menu)  
(Show IGMP Group information)  
>> IGMP Multicast# dump  
Note: Local groups (224.0.0.x) are not snooped and will not appear.  
Group VLAN Port Version Expires  
--------------- ------ ------- -------- ----------  
238.1.0.0  
238.1.0.4  
1
1
EXT1  
EXT1  
V2  
V2  
4:17  
4:18  
>> /info/l3/igmp/mrouter  
>> Mrouter# dump  
(Select Mrouter information menu)  
(Show IGMP Group information)  
>> IGMP Multicast Router# dump  
VLAN  
Port  
Version  
Expires  
Max Query Resp. Time  
-------  
-------  
--------- -------- -----------------------  
1
EXT4  
V2 static unknown  
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These commands display information about IGMP Groups and Mrouters learned through  
IGMP Snooping.  
Static Multicast Router  
A static multicast router (Mrouter) can be configured for a particular port on a particular  
VLAN. A static Mrouter does not have to be learned through IGMP Snooping.  
A total of 16 static Mrouters can be configured on the GbESM. Both internal and external ports  
can accept a static Mrouter.  
When you configure a static Mrouter on a VLAN, it replaces any dynamic Mrouters learned  
through IGMP Snooping.  
Configure a Static Multicast Router  
1. Configure a port to which the static Multicast Router is connected, and enter the appro-  
priate VLAN.  
>> /cfg/l3/igmp/mrouter  
>> Static Multicast Router# add EXT4  
Enter VLAN number: (1-4093) 1  
(Select IGMP Mrouter menu)  
(Add port EXT4 as Static Mrouter port)  
(Enter the VLAN number)  
Enter the version number of mrouter [1|2]: 2 (Enter the IGMP version number)  
2. Apply, verify, and save the configuration.  
>> Static Multicast Router# apply  
>> Static Multicast Router# cur  
>> Static Multicast Router# save  
(Apply the configuration)  
(View the configuration)  
(Save your changes)  
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IGMP Relay  
The GbESM can act as an IGMP Relay (or IGMP Proxy) device that relays IGMP multicast  
messages and traffic between an Mrouter and end stations. IGMP Relay allows the GbESM to  
participate in network multicasts with no configuration of the various multicast routing proto-  
cols, so you can deploy it in the network with minimal effort.  
To an IGMP host connected to the GbESM, IGMP Relay appears to be an IGMP multicast  
router (Mrouter). IGMP Relay sends Membership Queries to hosts, which respond by sending  
an IGMP response message. A host can also send an unsolicited Join message to the IGMP  
Relay.  
To a multicast router, IGMP Relay appears as a host. The Mrouter sends IGMP host queries to  
IGMP Relay, and IGMP Relay responds by forwarding IGMP host reports and unsolicited join  
messages from its attached hosts.  
IGMP Relay also forwards multicast traffic between the Mrouter and end stations, similar  
to IGMP Snooping.  
You can configure up to two Mrouters to use with IGMP Relay. One Mrouter acts as the pri-  
mary Mrouter, and one is the backup Mrouter. The GbESM uses health checks to select the pri-  
mary Mrouter.  
Configuration Guidelines  
Consider the following guidelines when you configure IGMP Relay:  
IGMP Relay and IGMP Snooping are mutually exclusive—if you enable IGMP Relay,  
you must turn off IGMP Snooping.  
Upstream Mrouters must be connected to external ports (EXT 1 - EXT 6).  
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Configure IGMP Relay  
Use the following procedure to configure IGMP Relay.  
1. Configure an IP interface and assign VLANs.  
>> /cfg/l3/if 2  
(Select IP interface 2)  
>> IP Interface 2# addr 10.10.1.1  
>> IP Interface 2# mask 255.255.255.0  
>> IP Interface 2# vlan 2  
(Configure IP address for IF 2)  
(Configure mask for IF 2)  
(Assign VLAN 2 to IF 2)  
(Select IP interface 3)  
>> /cfg/l3/if 3  
>> IP Interface 3# addr 10.10.1.2  
>> IP Interface 3# mask 255.255.255.0  
>> IP Interface 3# vlan 3  
(Configure IP address for IF 3)  
(Configure mask for IF 3)  
(Assign VLAN 3 to IF 3)  
2. Turn IGMP on.  
>> /cfg/l3/igmp/on  
(Turn on IGMP)  
3. Enable IGMP Relay and add VLANs to the downstream network.  
>> /cfg/l3/igmp/relay/ena  
>> IGMP Relay# add 2  
Vlan 2 added.  
(Enable IGMP Relay)  
(Add VLAN 2 to IGMP Relay)  
>> IGMP Relay# add 3  
Vlan 3 added.  
(Add VLAN 3 to IGMP Relay)  
4. Configure the upstream Mrouters.  
>> IGMP Relay# mrtr 1/addr 100.0.1.2/ena  
Current IP address:  
0.0.0.0  
New pending IP address: 100.0.1.2  
Current status: disabled  
New status:  
enabled  
>> Multicast router 1# ..  
>> IGMP Relay# mrtr 2/addr 100.0.2.4/ena  
Current IP address:  
0.0.0.0  
New pending IP address: 100.0.2.4  
Current status: disabled  
New status:  
enabled  
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5. Apply and save the configuration.  
>> Multicast router 2# apply  
>> Multicast router 2# save  
(Apply the configuration)  
(Save the configuration)  
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The following topics are discussed in this section:  
“FastLeave” on page 168  
“IGMP Filtering” on page 168  
FastLeave  
In normal IGMP operation, when the receives an IGMPv2 leave message, it sends a Group-  
Specific Query to determine if any other devices in the same group (and on the same port) are  
still interested in the specified multicast group traffic. The switch removes the affiliated port  
from that particular group, if the following conditions apply:  
If the switch does not receive an IGMP Membership Report within the query-response-  
interval.  
If no multicast routers have been learned on that port.  
With FastLeave enabled on the VLAN, a port can be removed immediately from the port list of  
the group entry when the IGMP Leave message is received, unless a multicast router was  
learned on the port.  
Enable FastLeave only on VLANs that have only one host connected to each physical port.  
IGMP Filtering  
With IGMP Filtering, you can allow or deny a port to send and receive multicast traffic to cer-  
tain multicast groups. Unauthorized users are restricted from streaming multicast traffic across  
the network.  
If access to a multicast group is denied, IGMP Membership Reports from the port are dropped,  
and the port is not allowed to receive IP multicast traffic from that group. If access to the mul-  
ticast group is allowed, Membership Reports from the port are forwarded for normal process-  
ing.  
To configure IGMP Filtering, you must globally enable IGMP filtering, define an IGMP filter,  
assign the filter to a port, and enable IGMP Filtering on the port. To define an IGMP filter, you  
must configure a range of IP multicast groups, choose whether the filter will allow or deny  
multicast traffic for groups within the range, and enable the filter.  
Configuring the Range  
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Each IGMP Filter allows you to set a start and end point that defines the range of IP addresses  
upon which the filter takes action. Each IP address in the range must be between 224.0.1.0 and  
239.255.255.255. If you choose anyas the start point, then the filter acts upon all addresses  
between 224.0.0.0 and the address entered as the end point. If you enter anyas the end point,  
then the filter acts upon all addresses between the address entered as the start point and  
239.255.255.255.  
Configuring the Action  
Each IGMP filter can allow or deny IP multicasts to the range of IP addresses configured. If  
you configure the filter to deny IP multicasts, then IGMP Membership Reports from multicast  
groups within the range are dropped. You can configure a secondary filter to allow IP multi-  
casts to a small range of addresses within a larger range that a primary filter is configured to  
deny. The two filters work together to allow IP multicasts to a small subset of addresses within  
the larger range of addresses.  
Configure IGMP Filtering  
1. Enable IGMP Filtering on the switch.  
>> /cfg/l3/igmp/igmpflt  
>> IGMP Filter# ena  
(Select IGMP Filtering menu)  
(Enable IGMP Filtering)  
Current status: disabled  
New status:  
enabled  
2. Define an IGMP filter.  
>> /cfg/l3/igmp/igmpflt  
>>IGMP Filter# filter 1  
(Select IGMP Filtering menu)  
(Select Filter 1 Definition menu)  
>>IGMP Filter 1 Definition# range 224.0.1.0 (Enter first IP address of the range)  
Current multicast address2: any  
Enter new multicast address2 or any: 226.0.0.0 (Enter second IP address)  
Current multicast address1:  
New pending multicast address1: 224.0.1.0  
Current multicast address2: any  
any  
New pending multicast address2: 226.0.0.0  
>>IGMP Filter 1 Definition# action deny  
>>IGMP Filter 1 Definition# ena  
(Deny multicast traffic)  
(Enable the filter)  
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3. Assign the IGMP filter to a port.  
>> /cfg/l3/igmp/igmpflt  
>>IGMP Filter# port EXT3  
(Select IGMP Filtering menu)  
(Select port EXT3)  
>>IGMP Port EXT3# filt ena  
Current port EXT3 filtering: disabled  
(Enable IGMP Filtering on the port)  
New port EXT3 filtering:  
>>IGMP Port EXT3# add 1  
>>IGMP Port EXT3# apply  
enabled  
(Add IGMP Filter 1 to the port)  
(Make your changes active)  
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CHAPTER 11  
Border Gateway Protocol  
Border Gateway Protocol (BGP) is an Internet protocol that enables routers on a network to  
share and advertise routing information with each other about the segments of the IP address  
space they can access within their network and with routers on external networks. BGP allows  
you to decide what is the “best” route for a packet to take from your network to a destination  
on another network rather than simply setting a default route from your border router(s) to your  
upstream provider(s). BGP is defined in RFC 1771.  
BGP feeds from as many as 16 BGP router peers. This allows more resilience and flexibility in  
“Internal Routing Versus External Routing” on page 172  
“Redistributing Routes” on page 179  
“BGP Attributes” on page 180  
“Selecting Route Paths in BGP” on page 181  
“BGP Failover Configuration” on page 182  
“Default Redistribution and Route Aggregation Example” on page 185  
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Internal Routing Versus External Routing  
To ensure effective processing of network traffic, every router on your network needs to know  
how to send a packet (directly or indirectly) to any other location/destination in your network.  
This is referred to as internal routing and can be done with static routes or using active, inter-  
nal dynamic routing protocols, such as RIP, RIPv2, and OSPF.  
Static routes should have a higher degree of precedence than dynamic routing protocols. If the  
destination route is not in the route cache, then the packets are forwarded to the default gate-  
way which may be incorrect if a dynamic routing protocol is enabled.  
It is also useful to tell routers outside your network (upstream providers or peers) about the  
routes you can access in your network. External networks (those outside your own) that are  
under the same administrative control are referred to as autonomous systems (AS). Sharing of  
routing information between autonomous systems is known as external routing.  
External BGP (eBGP) is used to exchange routes between different autonomous systems  
whereas internal BGP (iBGP) is used to exchange routes within the same autonomous system.  
An iBGP is a type of internal routing protocol you can use to do active routing inside your net-  
work. It also carries AS path information, which is important when you are an ISP or doing  
BGP transit.  
NOTE The iBGP peers must be part of a fully meshed network, as shown in Figure 11-1.  
BladeCenter  
Internet  
Figure 11-1 iBGP and eBGP  
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Typically, an AS has one or more border routers—peer routers that exchange routes with other  
ASs—and an internal routing scheme that enables routers in that AS to reach every other router  
and destination within that AS. When you advertise routes to border routers on other autono-  
mous systems, you are effectively committing to carry data to the IP space represented in the  
route being advertised. For example, if you advertise 192.204.4.0/24, you are declaring that if  
another router sends you data destined for any address in 192.204.4.0/24, you know how to  
carry that data to its destination.  
Forming BGP Peer Routers  
Two BGP routers become peers or neighbors once you establish a TCP connection between  
them. For each new route, if a peer is interested in that route (for example, if a peer would like  
to receive your static routes and the new route is static), an update message is sent to that peer  
containing the new route. For each route removed from the route table, if the route has already  
been sent to a peer, an update message containing the route to withdraw is sent to that peer.  
For each Internet host, you must be able to send a packet to that host, and that host has to have a  
path back to you. This means that whoever provides Internet connectivity to that host must have  
a path to you. Ultimately, this means that they must “hear a route” which covers the section of the  
IP space you are using; otherwise, you will not have connectivity to the host in question.  
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What is a Route Map?  
A route map is used to control and modify routing information. Route maps define conditions  
for redistributing routes from one routing protocol to another or controlling routing informa-  
tion when injecting it in and out of BGP. Route maps are used by OSPF only for redistributing  
routes. For example, a route map is used to set a preference value for a specific route from a  
peer router and another preference value for all other routes learned via the same peer router.  
For example, the following command is used to define a route map:  
>> # /cfg/l3/rmap 1  
(Select a route map)  
A route map allows you to match attributes, such as metric, network address, and AS number.  
It also allows users to overwrite the local preference metric and to append the AS number in  
the AS route. See “BGP Failover Configuration” on page 182.  
Alteon OS allows you to configure 32 route maps. Each route map can have up to eight access  
lists. Each access list consists of a network filter. A network filter defines an IP address and  
subnet mask of the network that you want to include in the filter. Figure 11-2 illustrates the  
relationship between route maps, access lists and network filters.  
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Route Maps  
(rmap)  
Network Filter  
(nwf)  
Access Lists  
(alist)  
1
1
---  
---  
---  
Route Map 1  
Route Map 2  
8
8
9
1
---  
---  
---  
8
16  
-----  
-----  
-----  
-----  
-----  
-----  
-----  
1
249  
256  
---  
---  
---  
Route Map 32  
8
Figure 11-2 Distributing Network Filters in Access Lists and Route Maps  
Incoming and Outgoing Route Maps  
You can have two types of route maps: incoming and outgoing. A BGP peer router can be con-  
figured to support up to eight route maps in the incoming route map list and outgoing route  
map list.  
If a route map is not configured in the incoming route map list, the router imports all BGP  
updates. If a route map is configured in the incoming route map list, the router ignores all  
unmatched incoming updates. If you set the action to deny, you must add another route map to  
permit all unmatched updates.  
Route maps in an outgoing route map list behave similar to route maps in an incoming route  
map list. If a route map is not configured in the outgoing route map list, all routes are adver-  
tised or permitted. If a route map in the outgoing route map list is set to permit, matched  
routes are advertised and unmatched routes are ignored.  
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Precedence  
You can set a priority to a route map by specifying a precedence value with the following  
command:  
>> /cfg/l3/rmap <x>/pre  
(Specify a precedence)  
The smaller the value the higher the precedence. If two route maps have the same precedence  
value, the smaller number has higher precedence.  
Configuration Overview  
To configure route maps, you need to do the following:  
1. Define network filter.  
>> # /cfg/l3/nwf 1  
(Specify a network filter number)  
>> IP Network Filter 1# addr <IP address> (Specify network address)  
>> IP Network Filter 1# mask <IP mask>  
>> IP Network Filter 1# ena  
(Specify network mask)  
(Enable network filter)  
Enter a filter number from 1 to 256. Specify the IP address and subnet mask of the network that  
you want to match. Enable the network filter. You can distribute up to 256 network filters  
among 32 route maps each containing eight access lists.  
2. (Optional) Define the criteria for the access list and enable it.  
Specify the access list and associate the network filter number configured in Step 1.  
>> # /cfg/l3/rmap 1  
(Specify a route map number)  
(Specify the access list number)  
(Specify the network filter number)  
(Define a metric)  
(Specify action for the access list)  
(Enable the access list)  
>> IP Route Map 1# alist 1  
>> IP Access List 1# nwf 1  
>> IP Access List 1# metric  
>> IP Access List 1# action deny  
>> IP Access List 1# ena  
Steps 2 and 3 are optional, depending on the criteria that you want to match. In Step 2, the net-  
work filter number is used to match the subnets defined in the network filter. In Step 3, the  
autonomous system number is used to match the subnets. Or, you can use both (Step 2 and Step  
3) criteria: access list (network filter) and access path (AS filter) to configure the route maps.  
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3. (Optional) Configure the attributes in the AS filter menu.  
>> # cfg/l3/rmap 1/aspath 1  
>> AS Filter 1# as 1  
(Specify the attributes in the filter)  
(Specify the AS number)  
>> AS Filter 1# action deny  
>> AS Filter 1# ena  
(Specify the action for the filter)  
(Enable the AS filter)  
4. Set up the BGP attributes.  
If you want to overwrite the attributes that the peer router is sending, then define the following  
BGP attributes:  
Specify the AS numbers that you want to prepend to a matched route and the local prefer-  
ence for the matched route.  
Specify the metric [Multi Exit Discriminator (MED)] for the matched route.  
>> # cfg/l3/rmap 1  
(Specify a route map number)  
(Specify the AS numbers to prepend)  
(Specify the local preference)  
(Specify the metric)  
>> IP Route Map 1# ap  
>> IP Route Map 1# lp  
>> IP Route Map 1# met  
5. Enable the route map.  
>> # cfg/l3/rmap 1/en  
(Enable the route map)  
6. Assign the route map to a peer router.  
Select the peer router and then add the route map to the incoming route map list,  
>> # cfg/l3/bgp/peer 1/addi  
(Add to the incoming route map)  
or to the outgoing route map list.  
>> # cfg/l3/bgp/peer 1/addo  
(Add to the outgoing route map)  
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Aggregating Routes  
Aggregation is the process of combining several different routes in such a way that a single  
route can be advertised, which minimizes the size of the routing table. You can configure  
aggregate routes in BGP either by redistributing an aggregate route into BGP or by creating an  
aggregate entry in the BGP routing table.  
When a subnet is redistributed from an Interior Gateway Protocol (IGP) into BGP, only the  
network route is injected into the BGP table. By default, this automatic summarization is dis-  
abled. To define the route to aggregate, use the following commands:  
>> # cfg/l3/bgp  
(Specify BGP)  
>> BGP aggr 1 # addr  
>> BGP aggr 1 # mask  
>> BGP aggr 1 # ena  
(Specify aggregate list number)  
(Enter aggregation network address)  
(Enter aggregation network mask)  
(Enable aggregation)  
An example of creating a BGP aggregate route is shown in “Default Redistribution and Route  
Aggregation Example” on page 185.  
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Redistributing Routes  
In addition to running multiple routing protocols simultaneously, Alteon OS software can  
redistribute information from one routing protocol to another. For example, you can instruct  
the switch to use BGP to readvertise static routes. This applies to all of the IP-based routing  
protocols.  
You can also conditionally control the redistribution of routes between routing domains by  
defining a method known as route maps between the two domains. For more information on  
route maps, see “What is a Route Map?” on page 174. Redistributing routes is another way of  
providing policy control over whether to export OSPF routes, fixed routes, static routes, and  
virtual IP address routes. For an example configuration, see “Default Redistribution and Route  
Aggregation Example” on page 185.  
Default routes can be configured using the following methods:  
Import  
Originate—The router sends a default route to peers if it does not have any default routes  
in its routing table.  
Redistribute—Default routes are either configured through the default gateway or learned  
via other protocols and redistributed to peer routers. If the default routes are from the  
default gateway, enable the static routes because default routes from the default gateway  
are static routes. Similarly, if the routes are learned from another routing protocol, make  
sure you enable that protocol for redistribution.  
None  
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BGP Attributes  
The following two BGP attributes are discussed in this section: Local preference and metric  
(Multi-Exit Discriminator).  
Local Preference Attribute  
When there are multiple paths to the same destination, the local preference attribute indicates  
the preferred path. The path with the higher preference is preferred (the default value of the  
local preference attribute is 100). Unlike the weight attribute, which is only relevant to the  
local router, the local preference attribute is part of the routing update and is exchanged among  
routers in the same AS.  
The local preference attribute can be set in one of two ways:  
/cfg/l3/bgp/pref  
This command uses the BGP default local preference method, affecting the outbound  
direction only.  
/cfg/l3/rmap/lp  
This command uses the route map local preference method, which affects both inbound  
and outbound directions.  
Metric (Multi-Exit Discriminator) Attribute  
This attribute is a hint to external neighbors about the preferred path into an AS when there are  
multiple entry points. A lower metric value is preferred over a higher metric value. The default  
value of the metric attribute is 0.  
Unlike local preference, the metric attribute is exchanged between ASs; however, a metric  
attribute that comes into an AS does not leave the AS.  
When an update enters the AS with a certain metric value, that value is used for decision mak-  
ing within the AS. When BGP sends that update to another AS, the metric is reset to 0.  
Unless otherwise specified, the router compares metric attributes for paths from external  
neighbors that are in the same AS.  
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Selecting Route Paths in BGP  
BGP selects only one path as the best path. It does not rely on metrics attributes to determine  
the best path. When the same network is learned via more than one BGP peer, BGP uses its  
policy for selecting the best route to that network. The BGP implementation on the GbE  
Switch Module uses the following criteria to select a path when the same route is received  
from multiple peers.  
1. Local fixed and static routes are preferred over learned routes.  
2. With iBGP peers, routes with higher local preference values are selected.  
3. In the case of multiple routes of equal preference, the route with lower AS path weight is  
selected.  
AS path weight = 128 x AS path length (number of autonomous systems transversed).  
4. In the case of equal weight and routes learned from peers that reside in the same AS, the  
lower metric is selected.  
NOTE A route with a metric is preferred over a route without a metric.  
5. The lower cost to the next hop of routes is selected.  
6. In the case of equal cost, the eBGP route is preferred over iBGP.  
7. If all routes are from eBGP, the route with the lower router ID is selected.  
When the path is selected, BGP puts the selected path in its routing table and propagates the  
path to its neighbors.  
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BGP Failover Configuration  
Use the following example to create redundant default gateways for a GbE Switch Module at a  
Web Host/ISP site, eliminating the possibility, should one gateway go down, that requests will  
be forwarded to an upstream router unknown to the switch.  
As shown in Figure 11-3, the switch is connected to ISP 1 and ISP 2. The customer negotiates  
with both ISPs to allow the switch to use their peer routers as default gateways. The ISP peer  
routers will then need to announce themselves as default gateways to the GbE Switch Module.  
GbE Switch  
Module  
VIP: 200.200.200.200  
IP: 200.200.200.1  
IP: 210.210.210.1  
BladeCenter  
Server 2  
Server 1  
IP: 200.200.200.10  
IP: 200.200.200.11  
Figure 11-3 BGP Failover Configuration Example  
On the GbE Switch Module, one peer router (the secondary one) is configured with a longer  
AS path than the other, so that the peer with the shorter AS path will be seen by the switch as  
the primary default gateway. ISP 2, the secondary peer, is configured with a metric of “3,”  
thereby appearing to the switch to be three router hops away.  
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1. Define the VLANs.  
For simplicity, both default gateways are configured in the same VLAN in this example. The  
gateways could be in the same VLAN or different VLANs.  
>> # /cfg/l2/vlan 1  
(Select VLAN 1)  
>> vlan 1# add <port number>  
(Add a port to the VLAN membership)  
2. Define the IP interfaces.  
The switch will need an IP interface for each default gateway to which it will be connected.  
Each interface will need to be placed in the appropriate VLAN. These interfaces will be used  
as the primary and secondary default gateways for the switch.  
>> IP# metrc strict  
>> IP# if 1  
>> IP Interface 1# ena  
(Set metric for default gateway)  
(Select default gateway interface 1)  
(Enable switch interface 1)  
>> IP Interface 1# addr 200.200.200.1  
>> IP Interface 1# mask 255.255.255.0  
>> IP Interface 1# ../ip/if 2  
>> IP Interface 2# ena  
(Configure IP address of interface 1)  
(Configure IP subnet address mask)  
(Select default gateway interface 2)  
(Enable switch interface 2)  
>> IP Interface 2# addr 210.210.210.1  
>> IP Interface 2# mask 255.255.255.0  
(Configure IP address of interface 2)  
(Configure IP subnet address mask)  
3. Enable IP forwarding.  
IP forwarding is turned on by default and is used for VLAN-to-VLAN (non-BGP) routing.  
Make sure IP forwarding is on if the default gateways are on different subnets or if the switch  
is connected to different subnets and those subnets need to communicate through the switch  
(which they almost always do).  
>> /cfg/l3/frwd on  
(Enable IP forwarding)  
NOTE To help eliminate the possibility for a Denial of Service (DoS) attack, the forwarding of  
directed broadcasts is disabled by default.  
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4. Configure BGP peer router 1 and 2.  
Peer 1 is the primary gateway router. Peer 2 is configured with a metric of “3.” The metric  
option is key to ensuring gateway traffic is directed to Peer 1, as it will make Peer 2 appear to  
be three router hops away from the switch. Thus, the switch should never use it unless Peer 1  
goes down.  
>> # /cfg/l3/bgp/peer 1  
(Select BGP peer router 1)  
>> BGP Peer 1# ena  
(Enable this peer configuration)  
(Set IP address for peer router 1)  
(Set IP interface for peer router 1)  
(Set remote AS number)  
>> BGP Peer 1# addr 200.200.200.2  
>> BGP Peer 1# if 200.200.200.1  
>> BGP Peer 1# ras 100  
>> BGP Peer 1# /cfg/l3/bgp/peer 2  
>> BGP Peer 2# ena  
>> BGP Peer 2# addr 210.210.210.2  
>> BGP Peer 2# if 210.210.210.1  
>> BGP Peer 2# ras 200  
(Select BGP peer router 2)  
(Enable this peer configuration)  
(Set IP address for peer router 2)  
(Set IP interface for peer router 2)  
(Set remote AS number)  
>> BGP Peer 2# metric 3  
(Set AS path length to 3 router hops)  
The metric command in the peer menu tells the GbE Switch Module to create an AS path of  
“3” when advertising via BGP.  
5. On the switch, apply and save your configuration changes.  
>> BGP Peer 2# apply  
>> save  
(Make your changes active)  
(Save for restore after reboot)  
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Default Redistribution and Route Aggregation  
Example  
This example shows you how to configure the switch to redistribute information from one  
routing protocol to another and create an aggregate route entry in the BGP routing table to min-  
imize the size of the routing table.  
As illustrated in Figure 11-4, you have two peer routers: an internal and an external peer router.  
Configure the GbE Switch Module to redistribute the default routes from AS 200 to AS 135.  
At the same time, configure for route aggregation to allow you to condense the number of  
routes traversing from AS 135 to AS 200.  
GbE  
Switch Module  
10.1.1.135  
BladeCenter  
Figure 11-4 Route Aggregation and Default Route Redistribution  
1. Configure the IP interface.  
2. Configure the AS number (AS 135) and router ID number (10.1.1.135).  
>> # /cfg/l3/bgp  
(Select BGP menu)  
>> Border Gateway Protocol# as 135  
(Specify an AS number)  
>> Border Gateway Protocol# .. /rtrid 10.1.1.135(Specify a router ID number)  
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3. Configure internal peer router 1 and external peer router 2.  
>> # /cfg/l3/bgp/peer 1  
>> BGP Peer 1# ena  
>> BGP Peer 1# addr 10.1.1.4  
>> BGP Peer 1# ras 135  
>> BGP Peer 1# ../peer 2  
>> BGP Peer 2# ena  
(Select internal peer router 1)  
(Enable this peer configuration)  
(Set IP address for peer router 1)  
(Set remote AS number)  
(Select external peer router 2)  
(Enable this peer configuration)  
(Set IP address for peer router 2)  
(Set remote AS number)  
>> BGP Peer 2# addr 20.20.20.2  
>> BGP Peer 2# ras 200  
4. Configure redistribution for Peer 1.  
>> # /cfg/l3/bgp/peer 1/redist  
>> BGP Peer 1# default redistribute  
>> BGP Peer 1# fixed ena  
(Select redistribute)  
(Set default to redistribute)  
(Enable fixed routes)  
5. Configure aggregation policy control.  
Configure the routes that you want aggregated.  
>> # /cfg/l3/bgp/aggr 1  
(Set aggregation number)  
>> BGP aggr 1# addr 135.0.0.0  
>> BGP Peer 1# mask 255.0.0.0  
(Add IP address to aggregate 1)  
(Add IP mask to aggregate 1)  
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CHAPTER 12  
OSPF  
Alteon OS supports the Open Shortest Path First (OSPF) routing protocol. The Alteon OS  
implementation conforms to the OSPF version 2 specifications detailed in Internet RFC 1583.  
“OSPF Overview” on page 188. This section provides information on OSPF concepts,  
such as types of OSPF areas, types of routing devices, neighbors, adjacencies, link state  
database, authentication, and internal versus external routing.  
“OSPF Implementation in Alteon OS” on page 193. This section describes how OSPF is  
implemented in Alteon OS, such as configuration parameters, electing the designated  
router, summarizing routes, defining route maps and so forth.  
“OSPF Configuration Examples” on page 204. This section provides step-by-step instruc-  
tions on configuring different configuration examples:  
Creating a simple OSPF domain  
Creating virtual links  
Summarizing routes  
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OSPF Overview  
OSPF is designed for routing traffic within a single IP domain called an Autonomous System  
(AS). The AS can be divided into smaller logical units known as areas.  
All routing devices maintain link information in their own Link State Database (LSDB). The  
LSDB for all routing devices within an area is identical but is not exchanged between different  
areas. Only routing updates are exchanged between areas, thereby significantly reducing the  
overhead for maintaining routing information on a large, dynamic network.  
The following sections describe key OSPF concepts.  
Types of OSPF Areas  
An AS can be broken into logical units known as areas. In any AS with multiple areas, one  
area must be designated as area 0, known as the backbone. The backbone acts as the central  
OSPF area. All other areas in the AS must be connected to the backbone. Areas inject sum-  
mary routing information into the backbone, which then distributes it to other areas as needed.  
As shown in Figure 12-1, OSPF defines the following types of areas:  
Stub Area—an area that is connected to only one other area. External route information is  
not distributed into stub areas.  
Not-So-Stubby-Area (NSSA)—similar to a stub area with additional capabilities. Routes  
originating from within the NSSA can be propagated to adjacent transit and backbone  
areas. External routes from outside the AS can be advertised within the NSSA but are not  
distributed into other areas.  
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Transit Area—an area that allows area summary information to be exchanged between  
routing devices. The backbone (area 0), any area that contains a virtual link to connect two  
areas, and any area that is not a stub area or an NSSA are considered transit areas.  
Backbone  
Area 0  
(Also a Transit Area)  
ABR  
ABR  
ABR  
Internal LSA  
Routes  
Virtual  
Link  
Transit Area  
Stub Area  
No External Routes  
from Backbone  
Not-So-Stubby Area  
(NSSA)  
ABR  
External LSA  
Routes  
ASBR  
Stub Area, NSSA,  
ABR = Area Border Router  
or Transit Area  
ASBR = Autonomous System  
Boundary Router  
Connected to Backbone  
via Virtual Link  
Non-OSPF Area  
RIP/BGP AS  
Figure 12-1 OSPF Area Types  
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Types of OSPF Routing Devices  
As shown in Figure 12-2, OSPF uses the following types of routing devices:  
Internal Router (IR)—a router that has all of its interfaces within the same area. IRs main-  
tain LSDBs identical to those of other routing devices within the local area.  
Area Border Router (ABR)—a router that has interfaces in multiple areas. ABRs maintain  
one LSDB for each connected area and disseminate routing information between areas.  
Autonomous System Boundary Router (ASBR)—a router that acts as a gateway between  
the OSPF domain and non-OSPF domains, such as RIP, BGP, and static routes.  
OSPF Autonomous System  
Backbone  
Area 0  
BGP  
Area 3  
Inter-Area Routes  
(Summary Routes)  
ABR  
External  
Routes  
ASBR  
ASBR  
RIP  
ABR  
ABR  
Internal  
Router  
Area 1  
Area 2  
Figure 12-2 OSPF Domain and an Autonomous System  
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Neighbors and Adjacencies  
In areas with two or more routing devices, neighbors and adjacencies are formed.  
Neighbors are routing devices that maintain information about each others’ health. To establish  
neighbor relationships, routing devices periodically send hello packets on each of their inter-  
faces. All routing devices that share a common network segment, appear in the same area, and  
have the same health parameters (helloand deadintervals) and authentication parameters  
respond to each other’s hello packets and become neighbors. Neighbors continue to send peri-  
odic hello packets to advertise their health to neighbors. In turn, they listen to hello packets to  
determine the health of their neighbors and to establish contact with new neighbors.  
The hello process is used for electing one of the neighbors as the area’s Designated Router  
(DR) and one as the area’s Backup Designated Router (BDR). The DR is adjacent to all other  
neighbors and acts as the central contact for database exchanges. Each neighbor sends its data-  
base information to the DR, which relays the information to the other neighbors.  
The BDR is adjacent to all other neighbors (including the DR). Each neighbor sends its data-  
base information to the BDR just as with the DR, but the BDR merely stores this data and does  
not distribute it. If the DR fails, the BDR will take over the task of distributing database infor-  
mation to the other neighbors.  
The Link-State Database  
OSPF is a link-state routing protocol. A link represents an interface (or routable path) from the  
routing device. By establishing an adjacency with the DR, each routing device in an OSPF area  
maintains an identical Link-State Database (LSDB) describing the network topology for its  
area.  
Each routing device transmits a Link-State Advertisement (LSA) on each of its interfaces.  
LSAs are entered into the LSDB of each routing device. OSPF uses flooding to distribute  
LSAs between routing devices.  
When LSAs result in changes to the routing device’s LSDB, the routing device forwards the  
changes to the adjacent neighbors (the DR and BDR) for distribution to the other neighbors.  
OSPF routing updates occur only when changes occur, instead of periodically. For each new  
route, if an adjacency is interested in that route (for example, if configured to receive static  
routes and the new route is indeed static), an update message containing the new route is sent  
to the adjacency. For each route removed from the route table, if the route has already been  
sent to an adjacency, an update message containing the route to withdraw is sent.  
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The Shortest Path First Tree  
The routing devices use a link-state algorithm (Dijkstra’s algorithm) to calculate the shortest  
path to all known destinations, based on the cumulative cost required to reach the destination.  
The cost of an individual interface in OSPF is an indication of the overhead required to send  
packets across it. The cost is inversely proportional to the bandwidth of the interface. A lower  
cost indicates a higher bandwidth.  
Internal Versus External Routing  
To ensure effective processing of network traffic, every routing device on your network needs  
to know how to send a packet (directly or indirectly) to any other location/destination in your  
network. This is referred to as internal routing and can be done with static routes or using  
active internal routing protocols, such as OSPF, RIP, or RIPv2.  
It is also useful to tell routers outside your network (upstream providers or peers) about the  
routes you have access to in your network. Sharing of routing information between autono-  
mous systems is known as external routing.  
Typically, an AS will have one or more border routers (peer routers that exchange routes with  
other OSPF networks) as well as an internal routing system enabling every router in that AS to  
reach every other router and destination within that AS.  
When a routing device advertises routes to boundary routers on other autonomous systems, it  
is effectively committing to carry data to the IP space represented in the route being advertised.  
For example, if the routing device advertises 192.204.4.0/24, it is declaring that if another  
router sends data destined for any address in the 192.204.4.0/24 range, it will carry that data to  
its destination.  
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Alteon OS supports a single instance of OSPF and up to 4 K routes on the network. The follow-  
“Summarizing Routes” on page 196  
“Default Routes” on page 197  
“Virtual Links” on page 198  
“Router ID” on page 199  
“Authentication” on page 199  
Configurable Parameters  
In Alteon OS, OSPF parameters can be configured through the Command Line Interfaces  
(CLI/ISCLI), Browser-Based Interface (BBI), or through SNMP. For more information, see  
Chapter 1, “Accessing the Switch.”  
The CLI supports the following parameters: interface output cost, interface priority, dead and  
hello intervals, retransmission interval, and interface transmit delay.  
In addition to the above parameters, you can also specify the following:  
Shortest Path First (SPF) interval—Time interval between successive calculations of the  
shortest path tree using the Dijkstra’s algorithm.  
Stub area metric—A stub area can be configured to send a numeric metric value such that  
all routes received via that stub area carry the configured metric to potentially influence  
routing decisions.  
Default routes—Default routes with weight metrics can be manually injected into transit  
areas. This helps establish a preferred route when multiple routing devices exist between  
two areas. It also helps route traffic to external networks.  
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Defining Areas  
If you are configuring multiple areas in your OSPF domain, one of the areas must be desig-  
nated as area 0, known as the backbone. The backbone is the central OSPF area and is usually  
physically connected to all other areas. The areas inject routing information into the backbone  
which, in turn, disseminates the information into other areas.  
Since the backbone connects the areas in your network, it must be a contiguous area. If the  
backbone is partitioned (possibly as a result of joining separate OSPF networks), parts of the  
AS will be unreachable, and you will need to configure virtual links to reconnect the parti-  
tioned areas (see “Virtual Links” on page 198).  
Up to three OSPF areas can be connected to the GbE Switch Module with Alteon OS software.  
To configure an area, the OSPF number must be defined and then attached to a network inter-  
face on the switch. The full process is explained in the following sections.  
An OSPF area is defined by assigning two pieces of information—an area index and an area  
ID. The command to define an OSPF area is as follows:  
>> # /cfg/l3/ospf/aindex <area index>/areaid <n.n.n.n>  
NOTE The aindexoption above is an arbitrary index used only on the switch and does not  
represent the actual OSPF area number. The actual OSPF area number is defined in the  
areaidportion of the command as explained in the following sections.  
Assigning the Area Index  
The aindex<area index> option is actually just an arbitrary index (0-2) used only by the  
GbE Switch Module. This index does not necessarily represent the OSPF area number, though  
for configuration simplicity, it should where possible.  
For example, both of the following sets of commands define OSPF area 0 (the backbone) and  
area 1 because that information is held in the area ID portion of the command. However, the  
first set of commands is easier to maintain because the arbitrary area indexes agree with the  
area IDs:  
Area index and area ID agree  
/cfg/l3/ospf/aindex 0/areaid 0.0.0.0 (Use index 0 to set area 0 in ID octet format)  
/cfg/l3/ospf/aindex 1/areaid 0.0.0.1 (Use index 1 to set area 1 in ID octet format)  
Area index set to an arbitrary value  
/cfg/l3/ospf/aindex 1/areaid 0.0.0.0 (Use index 1 to set area 0 in ID octet format)  
/cfg/l3/ospf/aindex 2/areaid 0.0.0.1 (Use index 2 to set area 1 in ID octet format)  
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Using the Area ID to Assign the OSPF Area Number  
The OSPF area number is defined in the areaid<IP address> option. The octet format is  
used in order to be compatible with two different systems of notation used by other OSPF net-  
work vendors. There are two valid ways to designate an area ID:  
Placing the area number in the last octet (0.0.0.n)  
Most common OSPF vendors express the area ID number as a single number. For exam-  
ple, the Cisco IOS-based router command “network1.1.1.00.0.0.255area1”  
defines the area number simply as “area1.” On the GbE Switch Module, using the last  
octet in the area ID, “area1” is equivalent to “areaid0.0.0.1”.  
Multi-octet (IP address)  
Some OSPF vendors express the area ID number in multi-octet format. For example,  
area2.2.2.2” represents OSPF area 2 and can be specified directly on the GbE  
Switch Module as “areaid2.2.2.2”.  
NOTE Although both types of area ID formats are supported, be sure that the area IDs are in  
the same format throughout an area.  
Attaching an Area to a Network  
Once an OSPF area has been defined, it must be associated with a network. To attach the area  
to a network, you must assign the OSPF area index to an IP interface that participates in the  
area. The format for the command is as follows:  
>> # /cfg/l3/ospf/if <interface number>/aindex <area index>  
For example, the following commands could be used to configure IP interface 14 for a pres-  
ence on the 10.10.10.1/24 network, to define OSPF area 1, and to attach the area to the net-  
work:  
>> # /cfg/l3/if 14  
>> IP Interface 14# addr 10.10.10.1  
(Select menu for IP interface 14)  
(Define IP address on backbone  
network)  
>> IP Interface 14# mask 255.255.255.0  
>> IP Interface 14# ena  
(Define IP mask on backbone)  
(Enable IP interface 14)  
>> IP Interface 14# ../ospf/aindex 1  
>> OSPF Area (index) 1 # areaid 0.0.0.1  
>> OSPF Area (index) 1 # ena  
(Select menu for area index 1)  
(Define area ID as OSPF area 1)  
(Enable area index 1)  
>> OSPF Area (index) 1 # ../if 14  
>> OSPF Interface 14# aindex 1  
(Select OSPF menu for interface 14)  
(Attach area to network on interface  
14)  
>> OSPF Interface 14# enable  
(Enable interface 14 for area index 1)  
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Interface Cost  
The OSPF link-state algorithm (Dijkstra’s algorithm) places each routing device at the root of a  
tree and determines the cumulative cost required to reach each destination. Usually, the cost is  
inversely proportional to the bandwidth of the interface. Low cost indicates high bandwidth.  
You can manually enter the cost for the output route with the following command:  
>> # /cfg/l3/ospf/if <OSPF interface number>/cost <cost value (1-65535)>  
Electing the Designated Router and Backup  
In any area with more than two routing devices, a Designated Router (DR) is elected as the  
central contact for database exchanges among neighbors, and a Backup Designated Router  
(BDR) is elected in case the DR fails.  
DR and BDR elections are made through the hello process. The election can be influenced by  
assigning a priority value to the OSPF interfaces on the GbE Switch Module. The command is  
as follows:  
>> # /cfg/l3/ospf/if <OSPF interface number>/prio <priority value (0-255)>  
A priority value of 255 is the highest, and 1 is the lowest. A priority value of 0 specifies that  
the interface cannot be used as a DR or BDR. In case of a tie, the routing device with the low-  
est router ID wins.  
Summarizing Routes  
Route summarization condenses routing information. Without summarization, each routing  
device in an OSPF network would retain a route to every subnet in the network. With summa-  
rization, routing devices can reduce some sets of routes to a single advertisement, reducing  
both the load on the routing device and the perceived complexity of the network. The impor-  
tance of route summarization increases with network size.  
Summary routes can be defined for up to 16 IP address ranges using the following command:  
<mask>  
where <range number> is a number 1 to 16, <IP address> is the base IP address for the range,  
and <mask> is the IP address mask for the range. For a detailed configuration example, see  
“Example 3: Summarizing Routes” on page 211.  
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Default Routes  
When an OSPF routing device encounters traffic for a destination address it does not recog-  
nize, it forwards that traffic along the default route. Typically, the default route leads upstream  
toward the backbone until it reaches the intended area or an external router.  
Each GbE Switch Module acting as an ABR automatically inserts a default route into each  
attached area. In simple OSPF stub areas or NSSAs with only one ABR leading upstream (see  
Area 1 in Figure 12-3), any traffic for IP address destinations outside the area is forwarded to  
the switch’s IP interface, and then into the connected transit area (usually the backbone). Since  
this is automatic, no further configuration is required for such areas.  
BladeCenter  
BladeCenter  
Figure 12-3 Injecting Default Routes  
If the switch is in a transit area and has a configured default gateway, it can inject a default  
route into rest of the OSPF domain. Use the following command to configure the switch to  
inject OSPF default routes:  
>> # /cfg/l3/ospf/default <metric value> <metric type (1 or 2)>  
In the command above, <metric value> sets the priority for choosing this switch for default  
route. The value nonesets no default and 1 sets the highest priority for default route. Metric  
type determines the method for influencing routing decisions for external routes.  
When the switch is configured to inject a default route, an AS-external LSA with link state  
ID 0.0.0.0 is propagated throughout the OSPF routing domain. This LSA is sent with the con-  
figured metric value and metric type.  
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The OSPF default route configuration can be removed with the command:  
>> # /cfg/l3/ospf/default none  
Virtual Links  
Usually, all areas in an OSPF AS are physically connected to the backbone. In some cases  
where this is not possible, you can use a virtual link. Virtual links are created to connect one  
area to the backbone through another non-backbone area (see Figure 12-1 on page 189).  
The area which contains a virtual link must be a transit area and have full routing information.  
Virtual links cannot be configured inside a stub area or NSSA. The area type must be defined  
as transitusing the following command:  
>> # /cfg/l3/ospf/aindex <area index>/type transit  
The virtual link must be configured on the routing devices at each endpoint of the virtual link,  
though they may traverse multiple routing devices. To configure a GbE Switch Module as one  
endpoint of a virtual link, use the following command:  
>> # /cfg/l3/ospf/virt <link number>/aindex <area index>/nbr <router  
ID>  
where <link number> is a value between 1 and 3, <area index> is the OSPF area index of the  
transit area, and <router ID> is the IP address of the virtual neighbor (nbr), the routing device  
at the target endpoint. Another router ID is needed when configuring a virtual link in the other  
direction. To provide the GbE Switch Module with a router ID, see the following section  
Router ID.  
For a detailed configuration example on Virtual Links, see “Example 2: Virtual Links” on page  
207.  
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Router ID  
Routing devices in OSPF areas are identified by a router ID. The router ID is expressed in IP  
address format. The IP address of the router ID is not required to be included in any IP inter-  
face range or in any OSPF area.  
The router ID can be configured in one of the following two ways:  
Dynamically—OSPF protocol configures the lowest IP interface IP address as the router  
ID. This is the default.  
Statically—Use the following command to manually configure the router ID:  
>> # /cfg/l3/rtrid <IP address>  
To modify the router ID from static to dynamic, set the router ID to 0.0.0.0, save the con-  
figuration, and reboot the GbE Switch Module. To view the router ID, enter:  
>> # /info/l3/ospf/gen  
Authentication  
OSPF protocol exchanges can be authenticated so that only trusted routing devices can partici-  
pate. This ensures less processing on routing devices that are not listening to OSPF packets.  
OSPF allows packet authentication and uses IP multicast when sending and receiving packets.  
Routers participate in routing domains based on predefined passwords. Alteon OS supports  
simple password (type 1 plain text passwords) and MD5 cryptographic authentication. This  
type of authentication allows a password to be configured per area.  
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Figure 12-4 shows authentication configured for area 0 with the password test. Simple authen-  
tication is also configured for the virtual link between area 2 and area 0. Area 1 is not config-  
ured for OSPF authentication.  
Application  
Switch 3  
Application  
Application  
switch 5  
BladeCenter  
Switch 4  
BladeCenter  
Figure 12-4 OSPF Authentication  
To configure simple plain text OSPF passwords on the switches shown in Figure 12-4 use the  
following commands:  
1. Enable OSPF authentication for Area 0 on switches 1, 2, and 3.  
>> # /cfg/l3/ospf/aindex 0/auth password  
(Turn on OSPF password authenti-  
cation)  
2. Configure a simple text password up to eight characters for each OSPF IP interface in  
Area 0 on switches 1, 2, and 3.  
>> # /cfg/l3/ospf/if 1  
>> OSPF Interface 1 # key test  
>> OSPF Interface 1 # ../if 2  
>> OSPF Interface 2 # key test  
>> OSPF Interface 1 # ../if 3  
>> OSPF Interface 3 # key test  
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3. Enable OSPF authentication for Area 2 on switch 4.  
>> # /cfg/l3/ospf/aindex 2/auth password  
(Turn on OSPF password authenti-  
cation)  
4. Configure a simple text password up to eight characters for the virtual link between Area  
2 and Area 0 on switches 2 and 4.  
>> # /cfg/l3/ospf/virt 1/key alteon  
Use the following commands to configure MD5 authentication on the switches shown in Fig-  
ure 12-4:  
1. Enable OSPF MD5 authentication for Area 0 on switches 1, 2, and 3.  
>> # /cfg/l3/ospf/aindex 0/auth md5  
(Turn on MD5 authentication)  
2. Configure MD5 key ID for Area 0 on switches 1, 2, and 3.  
>> # /cfg/l3/ospf/md5key 1/key test  
3. Assign MD5 key ID to OSPF interfaces on switches 1, 2, and 3.  
>> # /cfg/l3/ospf/if 1  
>> OSPF Interface 1 # mdkey 1  
>> OSPF Interface 1 # ../if 2  
>> OSPF Interface 2 # mdkey 1  
>> OSPF Interface 1 # ../if 3  
>> OSPF Interface 3 # mdkey 1  
4. Enable OSPF MD5 authentication for Area 2 on switch 4.  
>> # /cfg/l3/ospf/aindex 2/auth md5  
5. Configure MD5 key for the virtual link between Area 2 and Area 0 on switches 2 and 4.  
>> # /cfg/l3/ospf/md5key 2/key alteon  
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6. Assign MD5 key ID to OSPF virtual link on switches 2 and 4.  
>> # /cfg/l3/ospf/virt 1/mdkey 2  
Host Routes for Load Balancing  
Alteon OS implementation of OSPF includes host routes. Host routes are used for advertising  
network device IP addresses to external networks, accomplishing the following goals:  
ABR Load Sharing  
As a form of load balancing, host routes can be used for dividing OSPF traffic among mul-  
tiple ABRs. To accomplish this, each switch provides identical services but advertises a  
host route for a different IP address to the external network. If each IP address serves a dif-  
ferent and equal portion of the external world, incoming traffic from the upstream router  
should be split evenly among ABRs.  
ABR Failover  
Complementing ABR load sharing, identical host routes can be configured on each ABR.  
These host routes can be given different costs so that a different ABR is selected as the  
preferred route for each server and the others are available as backups for failover pur-  
poses.  
Equal Cost Multipath (ECMP)  
With equal cost multipath, a router potentially has several available next hops towards any  
given destination. ECMP allows separate routes to be calculated for each IP Type of Ser-  
vice. All paths of equal cost to a given destination are calculated, and the next hops for all  
equal-cost paths are inserted into the routing table.  
If redundant routes via multiple routing processes (such as OSPF, RIP, BGP, or static routes)  
exist on your network, the switch defaults to the OSPF-derived route.  
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OSPF Features Not Supported in This Release  
The following OSPF features are not supported in this release:  
Summarizing external routes  
Filtering OSPF routes  
Using OSPF to forward multicast routes  
Configuring OSPF on non-broadcast multi-access networks (such as frame relay, X.25,  
and ATM)  
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OSPF Configuration Examples  
A summary of the basic steps for configuring OSPF on the GbE Switch Module is listed here.  
Detailed instructions for each of the steps is covered in the following sections:  
1. Configure IP interfaces.  
One IP interface is required for each desired network (range of IP addresses) being assigned to  
an OSPF area on the switch.  
2. (Optional) Configure the router ID.  
The router ID is required only when configuring virtual links on the switch.  
3. Enable OSPF on the switch.  
4. Define the OSPF areas.  
5. Configure OSPF interface parameters.  
IP interfaces are used for attaching networks to the various areas.  
6. (Optional) Configure route summarization between OSPF areas.  
7. (Optional) Configure virtual links.  
8. (Optional) Configure host routes.  
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Example 1: Simple OSPF Domain  
In this example, two OSPF areas are defined—one area is the backbone and the other is a stub  
area. A stub area does not allow advertisements of external routes, thus reducing the size of the  
database. Instead, a default summary route of IP address 0.0.0.0 is automatically inserted into  
the stub area. Any traffic for IP address destinations outside the stub area will be forwarded to  
the stub area’s IP interface, and then into the backbone.  
BladeCenter  
BladeCenter  
nter  
Network  
10.10.12.0/24  
Network  
10.10.7.0/24  
Figure 12-5 A Simple OSPF Domain  
Follow this procedure to configure OSPF support as shown in Figure 12-5:  
1. Configure IP interfaces on each network that will be attached to OSPF areas.  
In this example, two IP interfaces are needed: one for the backbone network on 10.10.7.0/24  
and one for the stub area network on 10.10.12.0/24.  
>> # /cfg/l3/if 1  
(Select menu for IP interface 1)  
(Set IP address on backbone network)  
(Set IP mask on backbone network)  
(Enable IP interface 1)  
>> IP Interface 1 # addr 10.10.7.1  
>> IP Interface 1 # mask 255.255.255.0  
>> IP Interface 1 # enable  
>> IP Interface 1 # ../if 2  
(Select menu for IP interface 2)  
(Set IP address on stub area network)  
(Set IP mask on stub area network)  
(Enable IP interface 2)  
>> IP Interface 2 # addr 10.10.12.1  
>> IP Interface 2 # mask 255.255.255.0  
>> IP Interface 2 # enable  
2. Enable OSPF.  
>> IP Interface 2 # /cfg/l3/ospf/on  
(Enable OSPF on the switch)  
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3. Define the backbone.  
The backbone is always configured as a transit area using areaid0.0.0.0.  
>> Open Shortest Path First # aindex 0  
>> OSPF Area (index) 0 # areaid 0.0.0.0  
>> OSPF Area (index) 0 # type transit  
>> OSPF Area (index) 0 # enable  
(Select menu for area index 0)  
(Set the ID for backbone area 0)  
(Define backbone as transit type)  
(Enable the area)  
4. Define the stub area.  
>> OSPF Area (index) 0 # ../aindex 1  
>> OSPF Area (index) 1 # areaid 0.0.0.1  
>> OSPF Area (index) 1 # type stub  
>> OSPF Area (index) 1 # enable  
(Select menu for area index 1)  
(Set the area ID for OSPF area 1)  
(Define area as stub type)  
(Enable the area)  
5. Attach the network interface to the backbone.  
>> OSPF Area 1 # ../if 1  
>> OSPF Interface 1 # aindex 0  
>> OSPF Interface 1 # enable  
(Select OSPF menu for IP interface 1)  
(Attach network to backbone index)  
(Enable the backbone interface)  
6. Attach the network interface to the stub area.  
>> OSPF Interface 1 # ../if 2  
>> OSPF Interface 2 # aindex 1  
>> OSPF Interface 2 # enable  
(Select OSPF menu for IP interface 2)  
(Attach network to stub area index)  
(Enable the stub area interface)  
7. Apply and save the configuration changes.  
>> OSPF Interface 2 # apply  
>> OSPF Interface 2 # save  
(Global command to apply all changes)  
(Global command to save all changes)  
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Example 2: Virtual Links  
In the example shown in Figure 12-6, area 2 is not physically connected to the backbone as is  
usually required. Instead, area 2 will be connected to the backbone via a virtual link through  
area 1. The virtual link must be configured at each endpoint.  
Switch 2  
Application  
Switch 1  
BladeCenter  
BladeCenter  
Figure 12-6 Configuring a Virtual Link  
Configuring OSPF for a Virtual Link on Switch #1  
1. Configure IP interfaces on each network that will be attached to the switch.  
In this example, two IP interfaces are needed on Switch #1: one for the backbone network on  
10.10.7.0/24 and one for the transit area network on 10.10.12.0/24.  
>> # /cfg/l3/if 1  
(Select menu for IP interface 1)  
>> IP Interface 1 # addr 10.10.7.1  
(Set IP address on backbone network)  
>> IP Interface 1 # mask 255.255.255.0 (Set IP mask on backbone network)  
>> IP Interface 1 # enable  
(Enable IP interface 1)  
>> IP Interface 1 # ../if 2  
>> IP Interface 2 # addr 10.10.12.1  
(Select menu for IP interface 2)  
(Set IP address on transit area network)  
>> IP Interface 2 # mask 255.255.255.0 (Set IP mask on transit area network)  
>> IP Interface 2 # enable  
(Enable interface 2)  
2. Configure the router ID.  
A router ID is required when configuring virtual links. Later, when configuring the other end  
of the virtual link on Switch 2, the router ID specified here will be used as the target virtual  
neighbor (nbr) address.  
>> IP Interface 2 # /cfg/l3/rtrid 10.10.10.1 (Set static router ID on switch 1)  
3. Enable OSPF.  
>> IP # /cfg/l3/ospf/on  
(Enable OSPF on switch 1)  
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4. Define the backbone.  
>> Open Shortest Path First # aindex 0  
>> OSPF Area (index) 0 # areaid 0.0.0.0  
>> OSPF Area (index) 0 # type transit  
>> OSPF Area (index) 0 # enable  
(Select menu for area index 0)  
(Set the area ID for backbone area 0)  
(Define backbone as transit type)  
(Enable the area)  
5. Define the transit area.  
The area that contains the virtual link must be configured as a transit area.  
>> OSPF Area (index) 0 # ../aindex 1  
>> OSPF Area (index) 1 # areaid 0.0.0.1  
>> OSPF Area (index) 1 # type transit  
>> OSPF Area (index) 1 # enable  
(Select menu for area index 1)  
(Set the area ID for OSPF area 1)  
(Define area as transit type)  
(Enable the area)  
6. Attach the network interface to the backbone.  
>> OSPF Area (index) 1 # ../if 1  
>> OSPF Interface 1 # aindex 0  
>> OSPF Interface 1 # enable  
(Select OSPF menu for IP interface 1)  
(Attach network to backbone index)  
(Enable the backbone interface)  
7. Attach the network interface to the transit area.  
>> OSPF Interface 1 # ../if 2  
>> OSPF Interface 2 # aindex 1  
>> OSPF Interface 2 # enable  
(Select OSPF menu for IP interface 2)  
(Attach network to transit area index)  
(Enable the transit area interface)  
8. Configure the virtual link.  
The nbrrouter ID configured in this step must be the same as the router ID that will be config-  
ured for Switch #2 in Step 2 on page 209.  
>> OSPF Interface 2 # ../virt 1  
>> OSPF Virtual Link 1 # aindex 1  
>> OSPF Virtual Link 1 # nbr 10.10.14.1  
>> OSPF Virtual Link 1 # enable  
(Specify a virtual link number)  
(Specify the transit area for the virtual link)  
(Specify the router ID of the recipient)  
(Enable the virtual link)  
9. Apply and save the configuration changes.  
>> OSPF Interface 2 # apply  
>> OSPF Interface 2 # save  
(Global command to apply all changes)  
(Global command to save all changes)  
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Configuring OSPF for a Virtual Link on Switch #2  
1. Configure IP interfaces on each network that will be attached to OSPF areas.  
Two IP interfaces are needed on Switch #2: one for the transit area network on 10.10.12.0/24  
and one for the stub area network on 10.10.24.0/24.  
>> # /cfg/l3/if 1  
>> IP Interface 1 # addr 10.10.12.2  
(Select menu for IP interface 1)  
(Set IP address on transit area net-  
work)  
>
> IP Interface 1 # mask 255.255.255.0  
(Set IP mask on transit area network)  
(Enable IP interface 1)  
>> IP Interface 1 # enable  
>> IP Interface 1 # ../if 2  
>> IP Interface 2 # addr 10.10.24.1  
(Select menu for IP interface 2)  
(Set IP address on stub area network)  
(Enable IP interface 2)  
>> IP Interface 2 # mask 255.255.255.0  
>> IP Interface 2 # enable  
2. Configure the router ID.  
A router ID is required when configuring virtual links. This router ID should be the same one  
specified as the target virtual neighbor (nbr) on switch 1 in Step 8 on page 208.  
>> IP Interface 2 # /cfg/l3/rtrid 10.10.14.1 (Set static router ID on switch 2)  
3. Enable OSPF.  
>> IP# /cfg/l3/ospf/on  
(Enable OSPF on switch 2)  
4. Define the backbone.  
This version of Alteon OS requires that a backbone index be configured on the non-backbone  
end of the virtual link as follows:  
>> Open Shortest Path First # aindex 0  
>> OSPF Area (index) 0 # areaid 0.0.0.0  
>> OSPF Area (index) 0 # enable  
(Select the menu for area index 0)  
(Set the area ID for OSPF area 0)  
(Enable the area)  
5. Define the transit area.  
>> OSPF Area (index) 0 # ../aindex 1  
>> OSPF Area (index) 1 # areaid 0.0.0.1  
>> OSPF Area (index) 1 # type transit  
>> OSPF Area (index) 1 # enable  
(Select menu for area index 1)  
(Set the area ID for OSPF area 1)  
(Define area as transit type)  
(Enable the area)  
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6. Define the stub area.  
>> OSPF Area (index) 1 # ../aindex 2  
>> OSPF Area (index) 2 # areaid 0.0.0.2  
>> OSPF Area (index) 2 # type stub  
>> OSPF Area (index) 2 # enable  
(Select the menu for area index 2)  
(Set the area ID for OSPF area 2)  
(Define area as stub type)  
(Enable the area)  
7. Attach the network interface to the backbone.  
>> OSPF Area (index) 2 # ../if 1  
>> OSPF Interface 1 # aindex 1  
>> OSPF Interface 1 # enable  
(Select OSPF menu for IP interface 1)  
(Attach network to transit area index)  
(Enable the transit area interface)  
8. Attach the network interface to the transit area.  
>> OSPF Interface 1 # ../if 2  
>> OSPF Interface 2 # aindex 2  
>> OSPF Interface 2 # enable  
(Select OSPF menu for IP interface 2)  
(Attach network to stub area index)  
(Enable the stub area interface)  
9. Configure the virtual link.  
The nbrrouter ID configured in this step must be the same as the router ID that was config-  
ured for switch #1 in Step 2 on page 207.  
>> OSPF Interface 2 # ../virt 1  
>> OSPF Virtual Link 1 # aindex 1  
>> OSPF Virtual Link 1 # nbr 10.10.10.1  
>> OSPF Virtual Link 1 # enable  
(Specify a virtual link number)  
(Specify the transit area for the virtual link)  
(Specify the router ID of the recipient)  
(Enable the virtual link)  
10. Apply and save the configuration changes.  
>> OSPF Interface 2 # apply  
>> OSPF Interface 2 # save  
(Global command to apply all changes)  
(Global command to save all changes)  
Other Virtual Link Options  
You can use redundant paths by configuring multiple virtual links.  
Only the endpoints of the virtual link are configured. The virtual link path may traverse  
multiple routers in an area as long as there is a routable path between the endpoints.  
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Example 3: Summarizing Routes  
By default, ABRs advertise all the network addresses from one area into another area. Route  
summarization can be used for consolidating advertised addresses and reducing the perceived  
complexity of the network.  
If the network IP addresses in an area are assigned to a contiguous subnet range, you can con-  
figure the ABR to advertise a single summary route that includes all the individual IP  
addresses within the area.  
The following example shows one summary route from area 1 (stub area) injected into area 0  
(the backbone). The summary route consists of all IP addresses from 36.128.192.0 through  
36.128.254.255 except for the routes in the range 36.128.200.0 through 36.128.200.255.  
BladeCenter  
BladeCenter  
Figure 12-7 Summarizing Routes  
NOTE You can specify a range of addresses to prevent advertising by using the hide option. In  
this example, routes in the range 36.128.200.0 through 36.128.200.255 are kept private.  
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Follow this procedure to configure OSPF support as shown in Figure 12-7:  
1. Configure IP interfaces for each network which will be attached to OSPF areas.  
>> # /cfg/l3/if 1  
>> IP Interface 1 # addr 10.10.7.1  
(Select menu for IP interface 1)  
(Set IP address on backbone network)  
(Set IP mask on backbone network)  
(Enable IP interface 1)  
>> IP Interface 1 # mask 255.255.255.0  
>> IP Interface 1 # ena  
>> IP Interface 1 # ../if 2  
>> IP Interface 2 # addr 36.128.192.1  
(Select menu for IP interface 2)  
(Set IP address on stub area network)  
(Set IP mask on stub area network)  
(Enable IP interface 2)  
>> IP Interface 2 # mask 255.255.192.0  
>> IP Interface 2 # ena  
2. Enable OSPF.  
>> IP Interface 2 # /cfg/l3/ospf/on  
(Enable OSPF on the switch)  
(Select menu for area index 0)  
3. Define the backbone.  
>> Open Shortest Path First # aindex 0  
>> OSPF Area (index) 0 # areaid 0.0.0.0 (Set the ID for backbone area 0)  
>> OSPF Area (index) 0 # type transit  
>> OSPF Area (index) 0 # enable  
(Define backbone as transit type)  
(Enable the area)  
4. Define the stub area.  
>> OSPF Area (index) 0 # ../aindex 1  
(Select menu for area index 1)  
>> OSPF Area (index) 1 # areaid 0.0.0.1 (Set the area ID for OSPF area 1)  
>> OSPF Area (index) 1 # type stub  
>> OSPF Area (index) 1 # enable  
(Define area as stub type)  
(Enable the area)  
5. Attach the network interface to the backbone.  
>> OSPF Area (index) 1 # ../if 1  
>> OSPF Interface 1 # aindex 0  
>> OSPF Interface 1 # enable  
(Select OSPF menu for IP interface 1)  
(Attach network to backbone index)  
(Enable the backbone interface)  
6. Attach the network interface to the stub area.  
>> OSPF Interface 1 # ../if 2  
>> OSPF Interface 2 # aindex 1  
>> OSPF Interface 2 # enable  
(Select OSPF menu for IP interface 2)  
(Attach network to stub area index)  
(Enable the stub area interface)  
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7. Configure route summarization by specifying the starting address and mask of the range  
of addresses to be summarized.  
>> OSPF Interface 2 # ../range 1  
(Select menu for summary range)  
(Set base IP address of summary range)  
(Set mask address for summary range)  
(Inject summary route into backbone)  
(Enable summary range)  
>> OSPF Summary Range 1 # addr 36.128.192.0  
>> OSPF Summary Range 1 # mask 255.255.192.0  
>> OSPF Summary Range 1 # aindex 0  
>> OSPF Summary Range 1 # enable  
8. Use the hide command to prevent a range of addresses from advertising to the backbone.  
>> OSPF Interface 2 # ../range 2  
(Select menu for summary range)  
(Set base IP address)  
(Set mask address)  
>> OSPF Summary Range 2 # addr 36.128.200.0  
>> OSPF Summary Range 2 # mask 255.255.255.0  
>> OSPF Summary Range 2 # hide enable  
(Hide the range of addresses)  
9. Apply and save the configuration changes.  
>> OSPF Summary Range 2 # apply  
>> OSPF Summary Range 2 # save  
(Global command to apply all changes)  
(Global command to save all changes)  
Verifying OSPF Configuration  
Use the following commands to verify the OSPF configuration on your switch:  
/info/l3/ospf/general  
/info/l3/ospf/nbr  
/info/l3/ospf/dbase/dbsum  
/info/l3/ospf/route  
/stats/l3/route  
Refer to the Alteon OS Command Reference for information on the above commands.  
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Part 3: High Availability  
Fundamentals  
Internet traffic consists of myriad services and applications which use the Internet Protocol  
(IP) for data delivery. However, IP is not optimized for all the various applications. High  
Availability goes beyond IP and makes intelligent switching decisions to provide redundant  
network configurations.  
High Availability  
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High Availability  
GbE Switch Modules support high-availability network topologies through an enhanced  
implementation of the Virtual Router Redundancy Protocol (VRRP).  
The following topics are discussed in this chapter:  
“Layer 2 Failover” on page 218. This section discusses trunk failover without using  
VRRP.  
“VRRP Overview” on page 224. This section discusses VRRP operation and Alteon OS  
redundancy configurations.  
“Failover Methods” on page 227. This section describes the three modes of high availabil-  
ity.  
“Alteon OS extensions to VRRP” on page 230. This section describes VRRP enhance-  
ments implemented in Alteon OS.  
“Virtual Router Deployment Considerations” on page 231. This section describes issues to  
“High Availability Configurations” on page 233. This section discusses the more useful  
and easily deployed redundant configurations.  
“Active-Active Configuration” on page 233  
“Hot-Standby Configuration” on page 238  
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Layer 2 Failover  
The primary application for Layer 2 Failover is to support Network Adapter Teaming.  
With Network Adapter Teaming, the NICs on each server all share the same IP address,  
and are configured into a team. One NIC is the primary link, and the other is a standby link.  
For more details, refer to the NetXen 10 Gb Ethernet Adapter documentation.  
NOTE Only two links per server blade can be used for Layer 2 Trunk Failover  
(one primary and one backup). Network Adapter Teaming allows only one backup NIC for  
each server blade.  
Layer 2 Failover can be enabled on any trunk group in the GbE Switch Module, including  
LACP trunks. Trunks can be added to failover trigger groups such that if some (or all) of the  
links fail in a trigger, the switch disables all internal ports in the switch (unless VLAN Monitor  
is turned on). When the internal ports are disabled, it causes the NIC team on the affected  
server blades to failover from the primary to the backup NIC. This process is called a failover  
event.  
When the appropriate number of links in a trigger group return to service, the switch enables  
the internal ports. This causes the NIC team on the affected server blades to fail back to the pri-  
mary switch (unless Auto-Fallback is disabled on the NIC team). The backup switch processes  
traffic until the primary switch’s internal links come up, which takes up to five seconds.  
VLAN Monitor  
The VLAN Monitor allows L2 Failover to discern different VLANs. With VLAN Monitor  
turned on:  
If enough links in a trigger go down (see “Setting the Failover Limit” on page 219), the  
switch disables all internal ports that reside in the same VLAN membership as the trunk(s)  
in the trigger.  
When enough links in the trigger return to service, the switch enables the internal ports  
that reside in the same VLAN membership as the trunk(s) in the trigger.  
If you turn off the VLAN Monitor (/cfg/failovr/vlan/off), only one failover trigger  
is allowed. When a link failure occurs on the trigger, the switch disables all internal server-  
blade ports.  
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Setting the Failover Limit  
The failover limit lets you specify the minimum number of operational links required  
within each trigger before the trigger initiates a failover event. For example, if the limit is two  
(/cfg/l2/failovr/trigger x/limit 2), a failover event occurs when the number  
of operational links in the trigger is two or fewer. When you set the limit to zero, the switch  
triggers a failover event only when no links in the trigger are operational.  
L2 Failover with Other Features  
L2 Failover works together with Link Aggregation Control Protocol (LACP) and with  
Spanning Tree Protocol (STP), as described below.  
LACP  
Link Aggregation Control Protocol allows the switch to form dynamic trunks.  
You can use the admin key to add LACP trunks to a failover trigger. When you add an admin  
key to a trigger (/cfg/failovr/trigger x/amon/addkey), any LACP trunk with  
that admin key becomes a member of the trigger.  
Spanning Tree Protocol  
If Spanning Tree Protocol (STP) is enabled on the ports in a failover trigger, the switch moni-  
tors the port STP state rather than the link state. A port failure results when STP is not in a For-  
warding state (that is, Listening, Learning, Blocking, or No Link). The switch automatically  
disables the appropriate internal ports, based on the VLAN monitor.  
When the switch determines that ports in the trigger are in STP Forwarding state, then it auto-  
matically enables the appropriate internal ports, based on the VLAN monitor. The switch fails  
back to normal operation.  
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Configuration Guidelines  
This section provides important information about configuring L2 Failover:  
A failover trigger can monitor multiple static trunks or a single LACP key, but not both.  
With VLAN Monitor on, the following additional guidelines apply:  
All external ports in all trunks that are added to a single failover trigger must have the  
same VLAN membership and have the same PVID.  
Each failover trigger must operate on a different VLAN membership.  
Multiple failover triggers cannot operate on the same internal port.  
For each port in each trunk in a failover trigger, the trigger monitors the STP state  
only on the default PVID.  
L2 Failover Configurations  
Figure 13-1 is a simple example of Layer 2 Failover. One GbE Switch Module is the primary,  
and the other is used as a backup. In this example, all external ports on the primary switch  
belong to a single trunk group, with Layer 2 Failover enabled, and Failover Limit set to 2. If  
two or fewer links in trigger 1 remain active, the switch temporarily disables all internal server-  
blade ports that reside in VLAN 1. This action causes a failover event on Server 1 and Server  
2.  
Trigger 1  
Primary  
GbESM  
Server 1  
Server 2  
Server 3  
Internet  
Trigger 1  
Backup  
GbESM  
Server 4  
Enterprise  
Routing Switch  
BladeCenter  
VLAN 1:  
VLAN 2:  
VLAN Monitor = On  
Figure 13-1 Basic Layer 2 Failover  
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Figure 13-2 shows a configuration with two trunks, each in a different Failover Trigger.  
GbESM 1 is the primary switch for Server 1 and Server 2. GbESM 2 is the primary switch for  
Server 3 and Server 4. VLAN Monitor is turned on. STP is turned off.  
If all links go down in trigger 1, GbESM 1 disables all internal ports that reside in VLAN 1. If  
all links in trigger 2 go down, GbESM 1 disables all internal ports that reside in VLAN 2.  
Trigger 1  
GbESM 1  
Server 1  
Trigger 2  
Server 2  
Internet  
Server 3  
Trigger 1  
GbESM 2  
Server 4  
Trigger 2  
Enterprise  
Routing Switch  
BladeCenter  
VLAN 1:  
VLAN 2:  
VLAN Monitor = On  
Figure 13-2 Two trunks, each in a different Failover Trigger  
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Figure 13-3 shows a configuration with two trunks. VLAN Monitor is turned off, so only one  
Failover Trigger is configured on each switch. GbESM 1 is the primary switch for Server 1 and  
Server 2. GbESM 2 is the primary switch for Server 3 and Server 4. STP is turned off.  
If all links in trigger 1 go down, GbESM 1 disables all internal links to server blades.  
Trigger 1  
GbESM 1  
Server 1  
Server 2  
Internet  
Server 3  
Trigger 1  
GbESM 2  
Server 4  
Enterprise  
BladeCenter  
Routing Switch  
VLAN 1:  
VLAN 2:  
VLAN Monitor = Off  
Figure 13-3 Two trunks, one Failover Trigger  
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Configuring Trunk Failover  
The following procedure pertains to example 1, as shown in Figure 13-1.  
1. Configure Network Adapter Teaming on the servers.  
2. Define a trunk group on the GbESM.  
>> # /cfg/l2/trunk 1  
(Select trunk group 1)  
>> Trunk group 1# add EXT1  
>> Trunk group 1# add EXT2  
>> Trunk group 1# add EXT3  
>> Trunk group 1# ena  
(Add port EXT1 to trunk group 1)  
(Add port EXT2 to trunk group 1)  
(Add port EXT3 to trunk group 1)  
(Enable trunk group 1)  
3. Configure Failover parameters.  
>> # /cfg/failovr/on  
>> Failover# trigger 1  
>> Trigger 1# ena  
>> Trigger 1# limit 2  
>> Trigger 1# amon  
(Turn Failover on)  
(Select trigger group 1)  
(Enable trigger group 1)  
(Set Failover limit to 2 links)  
(Select Auto Monitor menu)  
(Add trunk group 1)  
>> Auto Monitor# addtrnk 1  
4. Apply and verify the configuration.  
>> Auto Monitor# apply  
(Make your changes active)  
>> Auto Monitor# cur  
(View current trunking configuration)  
5. Save your new configuration changes.  
>> Auto Monitor# save  
(Save for restore after reboot)  
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VRRP Overview  
In a high-availability network topology, no device can create a single point-of-failure for the  
network or force a single point-of-failure to any other part of the network. This means that  
your network will remain in service despite the failure of any single device. To achieve this  
usually requires redundancy for all vital network components.  
VRRP enables redundant router configurations within a LAN, providing alternate router paths  
for a host to eliminate single points-of-failure within a network. Each participating VRRP-  
capable routing device is configured with the same virtual router IP address and ID number.  
One of the virtual routers is elected as the master, based on a number of priority criteria, and  
assumes control of the shared virtual router IP address. If the master fails, one of the backup  
virtual routers will take control of the virtual router IP address and actively process traffic  
addressed to it.  
With VRRP, Virtual Interface Routers (VIR) allow two VRRP routers to share an IP interface  
across the routers. VIRs provide a single Destination IP (DIP) for upstream routers to reach  
various servers, and provide a virtual default Gateway for the server blades.  
VRRP Components  
Each physical router running VRRP is known as a VRRP router.  
Virtual Router  
Two or more VRRP routers can be configured to form a virtual router (RFC 2338). Each  
VRRP router may participate in one or more virtual routers. Each virtual router consists of a  
user-configured virtual router identifier (VRID) and an IP address.  
Virtual Router MAC Address  
The VRID is used to build the virtual router MAC Address. The five highest-order octets of the  
virtual router MAC Address are the standard MAC prefix (00-00-5E-00-01) defined in RFC  
2338. The VRID is used to form the lowest-order octet.  
Owners and Renters  
Only one of the VRRP routers in a virtual router may be configured as the IP address owner.  
This router has the virtual router’s IP address as its real interface address. This router responds  
to packets addressed to the virtual router’s IP address for ICMP pings, TCP connections, and  
so on.  
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There is no requirement for any VRRP router to be the IP address owner. Most VRRP installa-  
routers that are not the IP address owner are called renters.  
Master and Backup Virtual Router  
Within each virtual router, one VRRP router is selected to be the virtual router master. See  
“Selecting the Master VRRP Router” on page 226 for an explanation of the selection process.  
NOTE If the IP address owner is available, it will always become the virtual router master.  
The virtual router master forwards packets sent to the virtual router. It also responds to Address  
Resolution Protocol (ARP) requests sent to the virtual router's IP address. Finally, the virtual  
router master sends out periodic advertisements to let other VRRP routers know it is alive and  
its priority.  
Within a virtual router, the VRRP routers not selected to be the master are known as virtual  
router backups. Should the virtual router master fail, one of the virtual router backups becomes  
the master and assumes its responsibilities.  
Virtual Interface Router  
At Layer 3, a Virtual Interface Router (VIR) allows two VRRP routers to share an IP interface  
across the routers. VIRs provide a single Destination IP (DIP) for upstream routers to reach  
various destination networks, and provide a virtual default Gateway.  
NOTE Every VIR must be assigned to an IP interface, and every IP interface must be assigned  
to a VLAN. If no port in a VLAN has link up, the IP interface of that VLAN is down, and if the  
IP interface of a VIR is down, that VIR goes into INIT state.  
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VRRP Operation  
Only the virtual router master responds to ARP requests. Therefore, the upstream routers only  
forward packets destined to the master. The master also responds to ICMP ping requests. The  
backup does not forward any traffic, nor does it respond to ARP requests.  
If the master is not available, the backup becomes the master and takes over responsibility for  
packet forwarding and responding to ARP requests.  
Selecting the Master VRRP Router  
Each VRRP router is configured with a priority between 1–254. A bidding process determines  
which VRRP router is or becomes the master—the VRRP router with the highest priority.  
The master periodically sends advertisements to an IP multicast address. As long as the back-  
ups receive these advertisements, they remain in the backup state. If a backup does not receive  
an advertisement for three advertisement intervals, it initiates a bidding process to determine  
which VRRP router has the highest priority and takes over as master.  
If, at any time, a backup determines that it has higher priority than the current master does, it  
can preempt the master and become the master itself, unless configured not to do so. In pre-  
emption, the backup assumes the role of master and begins to send its own advertisements. The  
current master sees that the backup has higher priority and will stop functioning as the master.  
A backup router can stop receiving advertisements for one of two reasons—the master can be  
down, or all communications links between the master and the backup can be down. If the  
master has failed, it is clearly desirable for the backup (or one of the backups, if there is more  
than one) to become the master.  
NOTE If the master is healthy but communication between the master and the backup has failed,  
there will then be two masters within the virtual router. To prevent this from happening, config-  
ure redundant links to be used between the switches that form a virtual router.  
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Failover Methods  
With service availability becoming a major concern on the Internet, service providers are  
increasingly deploying Internet traffic control devices, such as application switches, in redun-  
dant configurations. Traditionally, these configurations have been hot-standby configurations,  
where one switch is active and the other is in a standby mode. A non-VRRP hot-standby con-  
figuration is shown in the figure below:  
Primary Switch  
IP: 200.200.200.100  
Internet  
Servers  
Secondary Switch  
IP: 200.200.200.101  
Figure 13-4 A Non-VRRP, Hot-Standby Configuration  
While hot-standby configurations increase site availability by removing single points-of-fail-  
ure, service providers increasingly view them as an inefficient use of network resources  
because one functional application switch sits by idly until a failure calls it into action. Service  
providers now demand that vendors' equipment support redundant configurations where all  
devices can process traffic when they are healthy, increasing site throughput and decreasing  
user response times when no device has failed.  
Alteon OS high availability configurations are based on VRRP. The Alteon OS implementa-  
tion of VRRP includes proprietary extensions.  
The Alteon OS implementation of VRRP supports the following modes of high availability:  
Active-Active—based on proprietary Alteon OS extensions to VRRP  
Hot-Standby—supports Network Adapter Teaming on your server blades  
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Active-Active Redundancy  
In an active-active configuration, shown in Figure 13-5, two switches provide redundancy for  
each other, with both active at the same time. Each switch processes traffic on a different sub-  
net. When a failure occurs, the remaining switch can process traffic on all subnets.  
For a configuration example, see “Active-Active Configuration” on page 233.  
Active (subnet A and C)  
GbESM 1  
Servers  
Internet  
GbESM 2  
Enterprise  
Routing Switch  
Active (subnet B and D)  
Figure 13-5 Active-Active Redundancy  
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Hot-Standby Redundancy  
The primary application for VRRP-based hot-standby is to support Server Load Balancing  
when you have configured Network Adapter Teaming on your server blades. With Network  
Adapter Teaming, the NICs on each server share the same IP address, and are configured into a  
team. One NIC is the primary link, and the others are backup links. For more details, refer to  
the NetXen 10 Gb Ethernet Adapter documentation.  
The hot-standby model is shown in Figure 13-6.  
Active  
GbESM 1  
10.10.10.1  
10.10.10.2  
Interswitch  
Link  
Enterprise  
Routing Switch  
GbESM 2  
Standby  
Figure 13-6 Hot-Standby Redundancy  
Virtual Router Group  
The virtual router group ties all virtual routers on the switch together as a single entity. By def-  
inition, hot-standby requires that all virtual routers failover as a group, and not individually. As  
members of a group, all virtual routers on the switch (and therefore the switch itself), are in  
either a master or standby state.  
The virtual router group cannot be used for active-active configurations or any other configura-  
tion that require shared interfaces.  
A VRRP group has the following characteristics:  
When enabled, all virtual routers behave as one entity, and all group settings override any  
individual virtual router settings.  
All individual virtual routers, once the VRRP group is enabled, assume the group’s track-  
ing and priority.  
When one member of a VRRP group fails, the priority of the group decreases, and the  
state of the entire switch changes from Master to Standby.  
Each VRRP advertisement can include up to 128 addresses. All virtual routers are advertised  
within the same packet, conserving processing and buffering resources.  
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Alteon OS extensions to VRRP  
This section describes the following VRRP enhancements that are implemented in Alteon OS:  
Tracking VRRP Router Priority  
Tracking VRRP Router Priority  
Alteon OS supports a tracking function that dynamically modifies the priority of a VRRP  
router, based on its current state. The objective of tracking is to have, whenever possible, the  
master bidding processes for various virtual routers in a LAN converge on the same switch.  
Tracking ensures that the selected switch is the one that offers optimal network performance.  
For tracking to have any effect on virtual router operation, pre-emption must be enabled.  
Alteon OS can track the attributes listed in Table 13-1:  
Table 13-1 VRRP Tracking Parameters  
Parameter  
Description  
Number of IP interfaces on the switch that Helps elect the virtual routers with the most available  
are active (“up”)  
/cfg/l3/vrrp/track/ifs  
routes as the master. (An IP interface is considered active  
when there is at least one active port on the same VLAN.)  
This parameter influences the VRRP router's priority in  
virtual interface routers.  
Number of active ports on the same VLAN Helps elect the virtual routers with the most available  
/cfg/l3/vrrp/track/ports  
ports as the master. This parameter influences the VRRP  
router's priority in virtual interface routers.  
Note: In a hot-standby configuration, only external ports  
are tracked.  
Number of virtual routers in master mode Useful for ensuring that traffic for any particular client/  
on the switch  
/cfg/l3/vrrp/track/vr  
server pair is handled by the same switch, increasing rout-  
ing efficiency. This parameter influences the VRRP  
router's priority in virtual interface routers.  
Each tracked parameter has a user-configurable weight associated with it. As the count associ-  
ated with each tracked item increases (or decreases), so does the VRRP router's priority, sub-  
ject to the weighting associated with each tracked item. If the priority level of a standby is  
greater than that of the current master, then the standby can assume the role of the master.  
See “Configuring the Switch for Tracking” on page 231 for an example on how to configure  
the switch for tracking VRRP priority.  
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Virtual Router Deployment Considerations  
Review the following issues described in this section to prevent network problems when  
deploying virtual routers:  
Assigning VRRP Virtual Router ID  
Configuring the Switch for Tracking  
Assigning VRRP Virtual Router ID  
During the software upgrade process, VRRP virtual router IDs will be automatically assigned  
if failover is enabled on the switch. When configuring virtual routers at any point after  
upgrade, virtual router ID numbers (/cfg/l3/vrrp/vr#/vrid) must be assigned. The  
virtual router ID may be configured as any number between 1 and 255.  
Configuring the Switch for Tracking  
Tracking configuration largely depends on user preferences and network environment. Con-  
sider the configuration shown in Figure 13-5 on page 228. Assume the following behavior on  
the network:  
Switch 1 is the master router upon initialization.  
If switch 1 is the master and it has one fewer active servers than switch 2, then switch 1  
remains the master.  
This behavior is preferred because running one server down is less disruptive than bring-  
ing a new master online and severing all active connections in the process.  
If switch 1 is the master and it has two or more active servers fewer than switch 2, then  
switch 2 becomes the master.  
If switch 2 is the master, it remains the master even if servers are restored on switch 1 such  
that it has one fewer or an equal number of servers.  
If switch 2 is the master and it has one active server fewer than switch 1, then switch 1  
becomes the master.  
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The user can implement this behavior by configuring the switch for tracking as follows:  
1. Set the priority for switch 1 to 101.  
2. Leave the priority for switch 2 at the default value of 100.  
3. On both switches, enable tracking based on ports (ports), interfaces (ifs), or virtual  
routers (vr). You can choose any combination of tracking parameters, based on your net-  
work configuration.  
NOTE There is no shortcut to setting tracking parameters. The goals must first be set and the  
outcomes of various configurations and scenarios analyzed to find settings that meet the goals.  
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GbE Switch Modules offer flexibility in implementing redundant configurations. This section  
discusses the more useful and easily deployed configurations:  
“Active-Active Configuration” on page 233  
“Hot-Standby Configuration” on page 238  
Active-Active Configuration  
Figure 13-7 shows an example configuration where two GbE Switch Modules are used as  
VRRP routers in an active-active configuration. In this configuration, both switches respond to  
packets.  
VIR 1: 192.168.1.200 (Master)  
L2 Switch  
VIR 2: 192.168.2.200 (Backup)  
1
2
NIC 1: 10.0.1.1/24  
NIC 2: 10.0.2.1/24  
GbESM 1  
Server 1  
Server 2  
Server 3  
Server 4  
5
NIC 1: 10.0.1.2/24  
NIC 2: 10.0.2.2/24  
Internet  
NIC 1: 10.0.1.3/24  
NIC 2: 10.0.2.3/24  
5
Enterprise  
Routing Switch  
1
2
NIC 1: 10.0.1.4/24  
NIC 2: 10.0.2.4/24  
GbESM 2  
VIR 1: 192.168.1.200 (Backup)  
VIR 2: 192.168.2.200 (Master)  
L2 Switch  
Figure 13-7 Active-Active High-Availability Configuration  
Although this example shows only two switches, there is no limit on the number of switches  
used in a redundant configuration. It is possible to implement an active-active configuration  
across all the VRRP-capable switches in a LAN.  
Each VRRP-capable switch in an active-active configuration is autonomous. Switches in a vir-  
tual router need not be identically configured.  
In the scenario illustrated in Figure 13-7, traffic destined for IP address 10.0.1.1 is forwarded  
through the Layer 2 switch at the top of the drawing, and ingresses GbESM 1 on port EXT1.  
Return traffic uses default gateway 1 (192.168.1.1). If the link between GbESM 1 and the  
Layer 2 switch fails, GbESM 2 becomes the Master because it has a higher priority. Traffic is  
forwarded to GbESM 2, which forwards it to GbESM 1 through port EXT5. Return traffic uses  
default gateway 2 (192.168.2.1), and is forwarded through the Layer 2 switch at the bottom of  
the drawing.  
To implement the active-active example, perform the following switch configuration.  
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Task 1: Configure GbESM 1  
1. Configure client and server interfaces.  
/cfg/l3/if 1  
(Select interface 1)  
>> IP Interface 1# addr 192.168.1.100  
>> IP Interface 1# vlan 10  
>> IP Interface 1# ena  
(Define IP address for interface 1)  
(Assign VLAN 10 to interface 1)  
(Enable interface 1)  
>> IP Interface 1# ..  
>> Layer 3# if 2  
(Select interface 2)  
>> IP Interface 2# addr 192.168.2.101  
>> IP Interface 2# vlan 20  
>> IP Interface 2# ena  
(Define IP address for interface 2)  
(Assign VLAN 20 to interface 2)  
(Enable interface 2)  
>> IP Interface 2# ..  
>> Layer 3# if 3  
(Select interface 3)  
>> IP Interface 3# addr 10.0.1.100  
>> IP Interface 3# mask 255.255.255.0  
>> IP Interface 3# ena  
(Define IP address for interface 3)  
(Define subnet mask for interface 3)  
(Enable interface 3)  
>> IP Interface 3# ..  
>> Layer 3# if 4  
(Select interface 4)  
>> IP Interface 4# addr 10.0.2.101  
>> IP Interface 4# mask 255.255.255.0  
>> IP Interface 4# ena  
(Define IP address for interface 4)  
(Define subnet mask for interface 4)  
(Enable interface 4)  
2. Configure the default gateways. Each default gateway points to a Layer 3  
router.  
/cfg/l3/gw 1  
(Select default gateway 1)  
>> Default gateway 1# addr 192.168.1.1  
>> Default gateway 1# ena  
>> Default gateway 1# ..  
>> Layer 3# gw 2  
(Point gateway to the first L3 router)  
(Enable the default gateway)  
(Select default gateway 2)  
>> Default gateway 2# addr 192.168.2.1  
>> Default gateway 2# ena  
(Point gateway to the second router)  
(Enable the default gateway)  
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3. Turn on VRRP and configure two Virtual Interface Routers.  
/cfg/l3/vrrp/on  
(Turn VRRP on)  
>> Virtual Router Redundancy Protocol# vr 1(Select virtual router 1)  
>> VRRP Virtual Router 1# vrid 1  
>> VRRP Virtual Router 1# if 1  
(Set VRID to 1)  
(Set interface 1)  
>> VRRP Virtual Router 1# addr 192.168.1.200(Define IP address)  
>> VRRP Virtual Router 1# ena  
>> VRRP Virtual Router 1# ..  
(Enable virtual router 1)  
(Enable virtual router 1)  
>> Virtual Router Redundancy Protocol# vr 2(Select virtual router 2)  
>> VRRP Virtual Router 2# vrid 2  
>> VRRP Virtual Router 2# if 2  
(Set VRID to 2)  
(Set interface 2)  
>> VRRP Virtual Router 2# addr 192.168.2.200(Define IP address)  
>> VRRP Virtual Router 2# ena (Enable virtual router 2)  
4. Enable tracking on ports. Set the priority of Virtual Router 1 to 101, so that it becomes  
the Master.  
/cfg/l3/vrrp/vr 1  
(Select VRRP virtual router 1)  
>> VRRP Virtual Router 1# track/ports/ena (Set tracking on ports)  
>> VRRP Virtual Router 1 Priority Tracking# ..  
>> VRRP Virtual Router 1# prio 101  
(Set the VRRP priority)  
>> VRRP Virtual Router 1# ..  
>> Virtual Router Redundancy Protocol# vr 2(Select VRRP virtual router 2)  
>> VRRP Virtual Router 1# track/ports/ena (Set tracking on ports)  
5. Configure ports.  
/cfg/l2/vlan 10  
(Select VLAN 10)  
>> VLAN 10# ena  
(Enable VLAN 10)  
>> VLAN 10# add ext1  
>> VLAN 10# ..  
(Add port EXT 1 to VLAN 10)  
>> Layer 2# vlan 20  
>> VLAN 20# ena  
(Select VLAN 20)  
(Enable VLAN 20)  
>> VLAN 20# add ext2  
(Add port EXT 2 to VLAN 20)  
6. Turn off Spanning Tree Protocol globally.  
/cfg/l2/stg 1/off  
(Turn off STG)  
>> Spanning Tree Group 1# apply  
>> Spanning Tree Group 1# save  
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Task 2: Configure GbESM 2  
1. Configure client and server interfaces.  
/cfg/l3/if 1  
(Select interface 1)  
>> IP Interface 1# addr 192.168.1.101  
>> IP Interface 1# vlan 10  
>> IP Interface 1# ena  
(Define IP address for interface 1)  
(Assign VLAN 10 to interface 1)  
(Enable interface 1)  
>> IP Interface 1# ..  
>> Layer 3# if 2  
(Select interface 2)  
>> IP Interface 2# addr 192.168.2.100  
>> IP Interface 2# vlan 20  
>> IP Interface 2# ena  
(Define IP address for interface 2)  
(Assign VLAN 20 to interface 2)  
(Enable interface 2)  
>> IP Interface 2# ..  
>> Layer 3# if 3  
(Select interface 3)  
>> IP Interface 3# addr 10.0.1.101  
>> IP Interface 3# mask 255.255.255.0  
>> IP Interface 3# ena  
(Define IP address for interface 3)  
(Define subnet mask for interface 3)  
(Enable interface 3)  
>> IP Interface 3# ..  
>> Layer 3# if 4  
(Select interface 4)  
>> IP Interface 4# addr 10.0.2.100  
>> IP Interface 4# mask 255.255.255.0  
>> IP Interface 4# ena  
(Define IP address for interface 4)  
(Define subnet mask for interface 4)  
(Enable interface 4)  
2. Configure the default gateways. Each default gateway points to a Layer 3  
router.  
/cfg/l3/gw 1  
(Select default gateway 1)  
>> Default gateway 1# addr 192.168.2.1  
>> Default gateway 1# ena  
>> Default gateway 1# ..  
>> Layer 3# gw 2  
(Point gateway to the first L3 router)  
(Enable the default gateway)  
(Select default gateway 2)  
>> Default gateway 2# addr 192.168.1.1  
>> Default gateway 2# ena  
(Point gateway to the second router)  
(Enable the default gateway)  
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3. Turn on VRRP and configure two Virtual Interface Routers.  
/cfg/l3/vrrp/on  
(Turn VRRP on)  
>> Virtual Router Redundancy Protocol# vr 1(Select virtual router 1)  
>> VRRP Virtual Router 1# vrid 1  
>> VRRP Virtual Router 1# if 1  
(Set VRID to 1)  
(Set interface 1)  
>> VRRP Virtual Router 1# addr 192.168.1.200(Define IP address)  
>> VRRP Virtual Router 1# ena  
>> VRRP Virtual Router 1# ..  
(Enable virtual router 1)  
(Enable virtual router 1)  
>> Virtual Router Redundancy Protocol# vr 2(Select virtual router 2)  
>> VRRP Virtual Router 2# vrid 2  
>> VRRP Virtual Router 2# if 2  
(Set VRID to 2)  
(Set interface 2)  
>> VRRP Virtual Router 2# addr 192.168.2.200(Define IP address)  
>> VRRP Virtual Router 2# ena (Enable virtual router 2)  
4. Enable tracking on ports. Set the priority of Virtual Router 2 to 101, so that it becomes  
the Master.  
/cfg/l3/vrrp/vr 1  
(Select VRRP virtual router 1)  
>> VRRP Virtual Router 1# track/ports/ena (Set tracking on ports)  
>> VRRP Virtual Router 1 Priority Tracking# ..  
>> VRRP Virtual Router 1# ..  
>> Virtual Router Redundancy Protocol# vr 2(Select VRRP virtual router 2)  
>> VRRP Virtual Router 2# track/ports/ena (Set tracking on ports)  
>> VRRP Virtual Router 2 Priority Tracking# ..  
>> VRRP Virtual Router 2# prio 101  
(Set the VRRP priority)  
5. Configure ports.  
/cfg/l2/vlan 10  
(Select VLAN 10)  
>> VLAN 10# ena  
(Enable VLAN 10)  
>> VLAN 10# add ext1  
>> VLAN 10# ..  
(Add port EXT 1 to VLAN 10)  
>> Layer 2# vlan 20  
>> VLAN 20# ena  
(Select VLAN 20)  
(Enable VLAN 20)  
>> VLAN 20# add ext2  
(Add port EXT 2 to VLAN 20)  
6. Turn off Spanning Tree Protocol globally. Apply and save changes.  
/cfg/l2/stg 1/off  
(Turn off STG)  
>> Spanning Tree Group 1# apply  
>> Spanning Tree Group 1# save  
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Hot-Standby Configuration  
The primary application for VRRP-based hot-standby is to support Network Adapter Teaming  
on your server blades. With Network Adapter Teaming, the NICs on each server share the  
same IP address, and are configured into a team. One NIC is the primary link, and the others  
are backup links. For more details, refer to the NetXen 10 Gb Ethernet Adapter documentation.  
A hot-standby configuration allows all processes to failover to a standby switch if any type of  
failure should occur. All Virtual Interface Routers (VIRs) are bundled into one Virtual Router  
group, and then they failover together. When there is a failure that causes the VRRP Master to  
failover to the Standby, then the original primary switch temporarily disables the internal  
server links, which, in turn, causes the NIC teams to failover as well.  
NOTE When using hot-standby redundancy, peer switches should have an equal number of  
connected ports.  
If hot-standby is implemented in a looped environment, the hot-standby feature automatically  
disables the hot-standby ports on the VRRP Standby. If the Master switch should failover to  
the Standby switch, it would change the hot-standby ports from disabled to forwarding, with-  
out relying on Spanning Tree or manual intervention. Therefore, Spanning Tree must be dis-  
abled.  
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Figure 13-8 illustrates a common hot-standby implementation on a single blade server. Notice  
that the BladeCenter server NICs are configured into a team that shares the same IP address  
across both NICs. Because only one link can be active at a time, the hot-standby feature con-  
trols the NIC failover by having the Standby switch disable its internal ports (holding down the  
server links).  
IF 1: 174.14.20.110  
IF 2: 10.1.1.110  
VIR 1: 174.14.20.100  
VIR 2: 10.1.1.100  
Active  
GbESM 1  
NIC 1 IP = 10.0.1.1  
Server 1  
Internet  
Hot Standby  
GbESM 2  
NIC 1 IP = 10.0.1.2  
Server 2  
Enterprise  
Routing Switch  
IF 1: 174.14.20.111  
IF 2: 10.1.1.111  
VIR 1: 174.14.20.100  
VIR 2: 10.1.1.100  
= Active Links  
= Standby Links  
Figure 13-8 Hot-Standby Configuration  
Task 1: Configure GbESM 1  
1. On GbESM 1, configure the interfaces for clients (174.14.20.110) and servers (10.1.1.110).  
/cfg/l3/if 1  
>> IP Interface 1# addr 174.14.20.110  
>> IP Interface 1# ena  
(Define IP address for interface 1)  
(Enable interface 1)  
>> IP Interface 1# ..  
>> Layer 3# if 2  
>> IP Interface 2# addr 10.1.1.110  
>> IP Interface 2# ena  
(Define IP address for interface 2)  
(Enable interface 2)  
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2. Configure Virtual Interface Routers.  
/cfg/l3/vrrp/on  
(Turn on VRRP)  
>> Virtual Router Redundancy Protocol# vr 1(Select Virtual Router 1)  
>> VRRP Virtual Router 1# ena  
>> VRRP Virtual Router 1# vrid 1  
>> VRRP Virtual Router 1# if 1  
(Enable VR 1)  
(Select the Virtual Router ID)  
(Select interface for VR 1)  
>> VRRP Virtual Router 1# addr 174.14.20.100(Define IP address for VR 1)  
>> VRRP Virtual Router 1# ..  
>> Virtual Router Redundancy Protocol# vr 2(Select Virtual Router 2)  
>> VRRP Virtual Router 2# ena  
>> VRRP Virtual Router 2# vrid 2  
>> VRRP Virtual Router 2# if 2  
(Enable VR 2)  
(Select the Virtual Router ID)  
(Select interface for VR 2)  
>> VRRP Virtual Router 2# addr 10.1.1.100 (Define IP address for VR 2)  
3. Enable VRRP Hot Standby.  
/cfg/l3/vrrp/hotstan ena  
(Enable Hot Standby)  
4. Configure VRRP Group parameters. Set the VRRP priority to 101, so that this switch is  
the Master.  
/cfg/l3/vrrp/group  
>> VRRP Virtual Router Group# ena  
>> VRRP Virtual Router Group# vrid 1  
>> VRRP Virtual Router Group# if 1  
>> VRRP Virtual Router Group# prio 101  
(Enable Virtual Router Group)  
(Set Virtual Router ID for Group)  
(Set interface for Group)  
(Set VRRP priority to 101)  
>> VRRP Virtual Router Group# track/ports ena(Enable tracking on ports)  
5. Turn off Spanning Tree Protocol globally. Apply and save changes.  
/cfg/l2/stg 1/off  
>> Spanning Tree Group 1# apply  
>> Spanning Tree Group 1# save  
(Turn off Spanning Tree)  
(Apply changes)  
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Task 2: Configure GbESM 2  
1. On GbESM 1, configure the interfaces for clients (174.14.20.111) and servers (10.1.1.111).  
/cfg/l3/if 1  
>> IP Interface 1# addr 174.14.20.111  
>> IP Interface 1# ena  
(Define IP address for interface 1)  
(Enable interface 1)  
>> IP Interface 1# ..  
>> Layer 3# if 2  
>> IP Interface 2# addr 10.1.1.111  
>> IP Interface 2# ena  
(Define IP address for interface 2)  
(Enable interface 2)  
2. Configure Virtual Interface Routers.  
/cfg/l3/vrrp/on  
(Turn on VRRP)  
>> Virtual Router Redundancy Protocol# vr 1(Select Virtual Router 1)  
>> VRRP Virtual Router 1# ena  
>> VRRP Virtual Router 1# vrid 1  
>> VRRP Virtual Router 1# if 1  
(Enable VR 1)  
(Select the Virtual Router ID)  
(Select interface for VR 1)  
>> VRRP Virtual Router 1# addr 174.14.20.100(Define IP address for VR 1)  
>> VRRP Virtual Router 1# ..  
>> Virtual Router Redundancy Protocol# vr 2(Select Virtual Router 2)  
>> VRRP Virtual Router 2# ena  
>> VRRP Virtual Router 2# vrid 2  
>> VRRP Virtual Router 2# if 2  
(Enable VR 2)  
(Select the Virtual Router ID)  
(Select interface for VR 2)  
>> VRRP Virtual Router 2# addr 10.1.1.100 (Define IP address for VR 2)  
3. Enable VRRP Hot Standby.  
/cfg/l3/vrrp/hotstan ena  
(Enable Hot Standby)  
4. Configure VRRP Group parameters. Use the default VRRP priority of 100, so that this  
switch is the Standby.  
/cfg/l3/vrrp/group  
>> VRRP Virtual Router Group# ena  
>> VRRP Virtual Router Group# vrid 1  
>> VRRP Virtual Router Group# if 1  
(Enable Virtual Router Group)  
(Set Virtual Router ID for Group)  
(Set interface for Group)  
>> VRRP Virtual Router Group# track/ports ena(Enable tracking on ports)  
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5. Turn off Spanning Tree Protocol globally. Apply and save changes.  
/cfg/l2/stg 1/off  
>> Spanning Tree Group 1# apply  
>> Spanning Tree Group 1# save  
(Turn off Spanning Tree)  
(Apply changes)  
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Part 4: Appendices  
This section describes the following topics:  
Troubleshooting  
RADIUS Server Configuration Notes  
Glossary  
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APPENDIX A  
This section discusses some tools to help you troubleshoot common problems on the GbE  
Switch Module:  
“Monitoring Ports” on page 246  
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Monitoring Ports  
The port mirroring feature in the Alteon OS allows you to attach a sniffer to a monitoring port  
that is configured to receive a copy of all packets that are forwarded from the mirrored port.  
Alteon OS enables you to mirror port traffic for all layer 2 and layer 3. Port mirroring can be  
used as a troubleshooting tool or to enhance the security of your network. For example, an IDS  
server can be connected to the monitor port to detect intruders attacking the network.  
As shown in Figure A-1, port EXT3 is monitoring ingress traffic (traffic entering the switch)  
on port EXT1 and egress traffic (traffic leaving the switch) on port EXT2. You can attach a  
device to port EXT3 to monitor the traffic on ports EXT1 and EXT2.  
Ingress  
Mirrored ports  
Egress  
Monitoring port  
Figure A-1 Monitoring Ports  
Figure A-1 shows two mirrored ports monitored by a single port. Similarly, you can have a sin-  
gle or groups of:  
one mirrored port to one monitored port  
more than two mirrored ports to one monitored port  
Alteon OS does not support a single port being monitored by multiple ports.  
Ingress and egress traffic is duplicated and sent to the monitor port after processing.  
NOTE The GbESM cannot mirror LACPDU packets.  
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NOTE Traffic on VLAN 4095 is not mirrored to the external ports.  
Port Mirroring behavior  
This section describes the composition of monitored packets in the GbE Switch Module, based  
on the configuration of the ports.  
If a tagged port's PVID is the same as its VLAN ID, then the egress traffic on that port is  
untagged. Therefore, the following port-mirroring cases are differentiated, as described below:  
Tagged or untagged frames from mirrored ports whose VLAN ID is the same as the moni-  
toring port's PVID: mirrored frames viewed at the monitoring port are untagged  
Tagged or untagged frames from mirrored ports whose VLAN ID is different than the  
monitoring port's PVID: mirrored frames viewed at the monitoring port are tagged with  
the VLAN ID of ingress/egress port for ingress/egress mirroring respectively.  
Layer 2 Port Mirroring  
In this scenario, you observe Layer 2 port mirroring.  
Same VLAN as Mirrored Port  
Both ports tagged: Tagged packet with VID of the VLAN to which the ports belong  
Mirrored port tagged, Monitoring port untagged: Untagged packet  
Mirrored port untagged, Monitoring port tagged: Tagged packet with VID of the  
VLAN to which both ports belong  
Both ports untagged: Untagged packet  
Different VLAN from Mirrored Port  
Both ports tagged: Tagged packet with VID of mirrored port  
Mirrored port tagged, Monitoring port untagged: Tagged packet with VID of mirrored  
port  
Mirrored port untagged, Monitoring port tagged: Tagged packet with VID of mirrored  
port  
Both ports untagged: Tagged packet with VID of mirrored port  
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Layer 3 Port Mirroring  
(Monitoring Port and Egress Port in the same GEA)  
In this scenario, you observe Layer 3 port mirroring on an egress port, and both the egress port  
and the monitoring port are in the same Gigabit Ethernet Aggregator (GEA) unit. To find out  
which GEA unit each port resides on, use the /info/geaportcommand.  
The monitoring port always shows a tagged packet with a VLAN ID (VID) of the egress port.  
NOTE In general, the GbESM mirrors all Layer 3 ingress packets after the packets are routed,  
that is, all Layer 3 packets observed at the monitoring port have source MAC address, destina-  
tion MAC address, VLAN, TTL, IP checksum changed as if they have gone through the rout-  
ing process to the egress port.  
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Layer 3 Port Mirroring (Both Ports in Different GEAs)  
In this scenario, you observe Layer 3 port mirroring on an egress port, but the egress port and  
the monitoring port reside on different Gigabit Ethernet Aggregator (GEA) units. To find out  
which GEA unit each port resides on, use the /info/geaportcommand.  
NOTE In general, the GbESM mirrors all Layer 3 ingress packets after the packets are routed,  
that is, all Layer 3 packets observed at the monitoring port have source MAC address, destina-  
tion MAC address, VLAN, TTL, IP checksum changed as if they have gone through the rout-  
ing process to the egress port.  
Same VLAN as Mirrored Port  
Both ports tagged: Tagged packet with VID of the VLAN to which the ports belong  
Mirrored port tagged, Monitoring port untagged: Untagged packet  
Mirrored port untagged, Monitoring port tagged: Tagged packet with VID of the  
VLAN to which the ports belong  
Both ports untagged: Untagged packet  
Different VLAN from Mirrored Port  
Both ports tagged: Tagged packet with VID of the VLAN to which the ports belong  
Mirrored port tagged, Monitoring port untagged: Tagged packet with VID of the  
VLAN to which the ports belong  
Mirrored port untagged, Monitoring port tagged: Tagged packet with VID of the  
VLAN to which the ports belong  
Both ports untagged: Tagged packet with VID of the VLAN to which the ports belong  
NOTE When the monitoring port belongs to a different VLAN, all mirrored packets have  
an 802.1q tag field with the VID of the VLAN to which the mirrored port belongs. The VID  
included in the tag field depends on which port is monitored.  
For example, assume a packet traverses from port EXT1 (VLAN 1) to EXT2 (VLAN 2), and is  
monitored on port EXT3. When you monitor EXT1, the packet’s tag includes the VID of  
VLAN 1. When you monitor EXT2, the packet’s tag includes the VID of VLAN 2.  
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Layer 3 Port Mirroring  
(MP Packets, Both Ports in the Same GEA)  
MP packets are generated by the management processor, such as routing packets between  
direct interfaces. In this scenario, the mirrored port and the monitoring port reside on the same  
Gigabit Ethernet Aggregator (GEA) unit. To find out which GEA unit each port resides on, use  
the /info/geaportcommand.  
The monitoring port always shows a tagged packet with a VLAN ID (VID) of the ingress port.  
Layer 3 Port Mirroring  
(MP Packets, Mirrored Port and Monitoring Port in Different GEAs)  
MP packets are generated by the management processor, such as a ping to the switch inter-  
faces. In this scenario, the mirrored port and the monitoring port reside on different Gigabit  
Ethernet Aggregator (GEA) units. To find out which GEA unit each port resides on, use  
the /info/geaportcommand.  
NOTE The switch doesn’t monitor Layer 3 egress-routed packets from the MP when the mir-  
ror port and the monitoring port are in different VLANs.  
Same VLAN as Mirrored Port  
Both ports tagged: Tagged packet with VID of the VLAN to which the ports belong  
Mirrored port tagged, Monitoring port untagged: Untagged packet  
Mirrored port untagged, Monitoring port tagged: Tagged packet with VID of the  
VLAN to which the ports belong  
Both ports untagged: Untagged packet  
Different VLAN from Mirrored Port  
Both ports tagged: Tagged packet with VID of the VLAN to which the ports belong  
Mirrored port tagged, Monitoring port untagged: Tagged packet with VID of the  
VLAN to which the ports belong  
Mirrored port untagged, Monitoring port tagged: Tagged packet with VID of the  
VLAN to which the ports belong  
Both ports untagged: Tagged packet with VID of the VLAN to which the ports belong  
NOTE When the monitoring port belongs to a different VLAN, all mirrored packets have  
an 802.1q tag field with the VID of the VLAN to which the mirrored port belongs. The VID  
included in the tag field depends on which port is monitored.  
For example, assume a packet traverses from port EXT1 (VLAN 1) to EXT2 (VLAN 2), and is  
monitored on port EXT3. When you monitor EXT1, the packet’s tag includes the VID of  
VLAN 1. When you monitor EXT2, the packet’s tag includes the VID of VLAN 2.  
250 Appendix A: Troubleshooting  
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Configuring Port Mirroring  
To configure port mirroring for the example shown in Figure A-1,  
1. Specify the monitoring port.  
>> # /cfg/pmirr/monport EXT3  
(Select port EXT3 for monitoring)  
2. Select the ports that you want to mirror.  
>> Port EXT3 # add EXT1  
(Select port EXT1 to mirror)  
>> Enter port mirror direction [in, out, or both]: in  
(Monitor ingress traffic on port EXT1)  
(Select port EXT2 to mirror)  
>> Enter port mirror direction [in, out, or both]: out  
(Monitor egress traffic on port EXT2)  
>> Port EXT3 # add EXT2  
3. Enable port mirroring.  
>> # /cfg/pmirr/mirr ena  
(Enable port mirroring)  
4. Apply and save the configuration.  
>> PortMirroring# apply  
>> PortMirroring# save  
(Apply the configuration)  
(Save the configuration)  
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5. View the current configuration.  
>> PortMirroring# cur  
(Display the current settings)  
Port mirroring is enabled  
Monitoring Ports  
INT1  
INT2  
INT3  
INT4  
Mirrored Ports  
none  
none  
none  
none  
none  
INT5  
-----  
-----  
-----  
EXT1  
none  
none  
EXT2  
EXT3  
(EXT1, in) (EXT2, out)  
EXT4  
EXT5  
EXT6  
none  
none  
none  
252 Appendix A: Troubleshooting  
42C4911, January 2007  
 
APPENDIX B  
RADIUS Server Configuration Notes  
Use the following information to modify your RADIUS configuration files for the Nortel  
Networks BaySecure Access Control RADIUS server, to provide authentication for users of  
the GbE Switch Module.  
1. Create a dictionary file called alteon.dct, with the following content:  
###################################################################  
# alteon.dct - RADLINX Alteon dictionary  
#
# (See README.DCT for more details on the format of this file)  
###################################################################  
#
# Use the Radius specification attributes in lieu of the  
# RADLINX Alteon ones  
#
@radius.dct  
#
# Define additional RADLINX Alteon parameters  
# (add RADLINX Alteon specific attributes below)  
ATTRIBUTE Radlinx-Vendor-Specific 26 [vid=648 data=string] R  
##################################################################  
# alteon.dct - RADLINX Alteon dictionary  
###################################################################  
#Define Alteon GbESM Layer 2 & Layer 3 dictionary  
#@radius.dct  
@alteon.dct  
VALUE  
VALUE  
Service-Type  
Service-Type  
user  
oper  
255  
252  
##################################################################  
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Alteon OS Application Guide  
2. Open the dictiona.dcmfile, and add the following line (as in the example):  
@alteon.dct  
###################################################################  
# dictiona.dcm  
###################################################################  
# Generic Radius  
@radius.dct  
#
# Specific Implementations (vendor specific)  
#
@pprtl2l3.dct  
@acc.dct  
@accessbd.dct  
@alteon.dct  
.
.
.
##################################################################  
# dictiona.dcm  
##################################################################  
3. Open the vendor file (vendor.ini), and add the following data to the Vendor-Product  
identification list:  
vendor-product  
dictionary  
ignore-ports  
help-id  
= Alteon Blade-server module  
= alteon  
= no  
= 0  
254 Appendix B: RADIUS Server Configuration Notes  
42C4911, January 2007  
 
Glossary  
DIP (Destination IP  
Address)  
The destination IP address of a frame.  
Dport (Destination  
Port)  
The destination port (application socket: for example, http-80/https-443/DNS-53)  
NAT (Network Address Any time an IP address is changed from one source IP or destination IP address to another  
Translation)  
address, network address translation can be said to have taken place. In general, half NAT  
is when the destination IP or source IP address is changed from one address to another.  
Full NAT is when both addresses are changed from one address to another. No NAT is  
when neither source nor destination IP addresses are translated.  
Preemption  
Priority  
In VRRP, preemption will cause a Virtual Router that has a lower priority to go into  
backup should a peer Virtual Router start advertising with a higher priority.  
In VRRP, the value given to a Virtual Router to determine its ranking with its peer(s). Min-  
imum value is 1 and maximum value is 254. Default is 100. A higher number will win out  
for master designation.  
Proto (Protocol)  
The protocol of a frame. Can be any value represented by a 8-bit value in the IP header  
adherent to the IP specification (for example, TCP, UDP, OSPF, ICMP, and so on.)  
SIP (Source IP Address) The source IP address of a frame.  
SPort (Source Port)  
Tracking  
The source port (application socket: for example, HTTP-80/HTTPS-443/DNS-53).  
In VRRP, a method to increase the priority of a virtual router and thus master designation  
(with preemption enabled). Tracking can be very valuable in an active/active configura-  
tion.  
You can track the following:  
ifs: Active IP interfaces on the Web switch (increments priority by 2 for each)  
ports: Active ports on the same VLAN (increments priority by 2 for each)  
vrs: Number of virtual routers in master mode on the switch  
VIR (Virtual Interface  
Router)  
A VRRP address that is an IP interface address shared between two or more virtual rout-  
ers.  
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Virtual Router  
A shared address between two devices utilizing VRRP, as defined in RFC 2338. One vir-  
tual router is associated with an IP interface. This is one of the IP interfaces that the switch  
is assigned. All IP interfaces on the GbE Switch Modules must be in a VLAN. If there is  
more than one VLAN defined on the Web switch, then the VRRP broadcasts will only be  
sent out on the VLAN of which the associated IP interface is a member.  
VRID (Virtual Router  
Identifier)  
In VRRP, a value between 1 and 255 that is used by each virtual router to create its MAC  
address and identify its peer for which it is sharing this VRRP address. The VRRP MAC  
address as defined in the RFC is 00-00-5E-00-01-{VRID}. If you have a VRRP address  
that two switches are sharing, then the VRID number needs to be identical on both  
switches so each virtual router on each switch knows whom to share with.  
VRRP (Virtual Router  
A protocol that acts very similarly to Cisco's proprietary HSRP address sharing protocol.  
Redundancy Protocol) The reason for both of these protocols is so devices have a next hop or default gateway that  
is always available. Two or more devices sharing an IP interface are either advertising or  
listening for advertisements. These advertisements are sent via a broadcast message to an  
address such as 224.0.0.18.  
With VRRP, one switch is considered the master and the other the backup. The master is  
always advertising via the broadcasts. The backup switch is always listening for the broad-  
casts. Should the master stop advertising, the backup will take over ownership of the  
VRRP IP and MAC addresses as defined by the specification. The switch announces this  
change in ownership to the devices around it by way of a Gratuitous ARP, and advertise-  
ments. If the backup switch didn't do the Gratuitous ARP the Layer 2 devices attached to  
the switch would not know that the MAC address had moved in the network. For a more  
detailed description, refer to RFC 2338.  
256 Glossary  
42C4911, January 2007  
 
Index  
Symbols  
C
........................................................................ 161  
[ ]....................................................................... 18  
Cisco EtherChannel .......................................96, 99  
CIST ................................................................121  
Class of Service queue .......................................140  
command conventions..........................................18  
Command Line Interface ....................................193  
configuration rules  
Numerics  
802.1Q VLAN tagging......................................... 80  
port mirroring ...............................................96  
spanning tree ................................................96  
Trunking......................................................96  
VLANs........................................................96  
configuring  
A
accessing the switch  
LDAP ......................................................... 53  
RADIUS authentication................................. 44  
security........................................................ 43  
using the Browser-based Interface................... 33  
active-active redundancy.................................... 228  
administrator account........................................... 47  
aggregating routes ............................................. 178  
example..................................................... 185  
application ports................................................ 127  
authenticating, in OSPF ..................................... 199  
autonomous systems (AS) .................................. 192  
BGP failover ..............................................182  
IP routing...................................................148  
OSPF.........................................................204  
port trunking.................................................98  
spanning tree groups....................................113  
D
default gateway .................................................147  
configuration example .................................149  
default password..................................................47  
default route  
OSPF.........................................................197  
Differentiated Services Code Point (DSCP)..........134  
B
BBI  
See Browser-Based Interface........................ 193  
Border Gateway Protocol (BGP)......................... 171  
attributes.................................................... 180  
failover configuration.................................. 182  
route aggregation ........................................ 178  
route maps ................................................. 174  
selecting route paths.................................... 181  
Bridge Protocol Data Unit (BPDU) ..................... 107  
broadcast domains....................................... 75, 150  
Browser-Based Interface.................................... 193  
E
End user access control  
configuring...................................................61  
EtherChannel ......................................................94  
as used with port trunking ........................96, 99  
Extensible Authentication Protocol over LAN (EAPoL)  
68  
external routing .........................................172, 192  
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Alteon OS Application Guide  
IP routing  
cross-subnet example .................................. 145  
F
Failover.............................................................218  
failover  
overview ....................................................227  
fault tolerance  
port trunking .................................................95  
fragmenting jumbo frames ..........................144, 147  
frame tagging. See VLANs tagging.  
default gateway configuration....................... 149  
IP interface configuration..................... 148, 151  
IP subnets .................................................. 145  
network diagram......................................... 145  
subnet configuration example ....................... 148  
switch-based topology ................................. 146  
IP subnets ......................................................... 146  
routing............................................... 145, 146  
VLANs........................................................ 75  
ISL Trunking ...................................................... 94  
G
gateway. See default gateway.  
J
H
jumbo frames  
high-availability.................................................217  
Host routes  
OSPF.........................................................202  
hot-standby redundancy......................................229  
HP-OpenView .....................................................36  
fragmenting to normal size................... 144, 147  
routing............................................... 144, 147  
L
LACP............................................................... 101  
LDAP  
authentication............................................... 53  
Link Aggregation Control Protocol ..................... 101  
logical segment. See IP subnets.  
I
IBM Director.......................................................36  
ICMP................................................................126  
IEEE standards  
LSAs................................................................ 191  
802.1d........................................................106  
802.1s ................................................117, 121  
802.1x..........................................................68  
IGMP........................................................126, 161  
IGMP Relay ......................................................165  
IGMP Snooping.................................................162  
incoming route maps ..........................................175  
internal routing ..........................................172, 192  
Internet Group Management Protocol (IGMP) ......161  
IP address  
M
management module............................................ 24  
manual style conventions ..................................... 18  
meter................................................................ 131  
mirroring ports .................................................. 246  
monitoring ports................................................ 246  
MSTP............................................................... 121  
multi-links between switches  
using port trunking........................................ 93  
multiple spanning tree groups ............................. 111  
Multiple Spanning Tree Protocol......................... 121  
routing example...........................................148  
IP interfaces  
example configuration..........................148, 151  
N
network management........................................... 36  
258 Index  
42C4911, January 2007  
 
Alteon OS Application Guide  
O
R
OSPF  
RADIUS  
area types................................................... 188  
authentication ...............................................44  
port 1812 and 1645......................................127  
port 1813 ...................................................127  
SSH/SCP .....................................................60  
Rapid Spanning Tree Protocol.............................118  
Rapid Spanning Tree Protocol (RSTP).................118  
redistributing routes ...........................174, 179, 185  
redundancy  
active-active ...............................................228  
hot-standby ................................................229  
re-mark.............................................................131  
RIP (Routing Information Protocol)  
advertisements............................................156  
distance vector protocol ...............................155  
hop count ...................................................155  
metric ........................................................155  
TCP/IP route information.......................16, 155  
version 1 ....................................................155  
route aggregation.......................................178, 185  
route maps ........................................................174  
configuring.................................................176  
incoming and outgoing ................................175  
route paths in BGP.............................................181  
Router ID  
OSPF.........................................................199  
routers ......................................................146, 149  
border........................................................192  
peer...........................................................192  
port trunking.................................................94  
switch-based routing topology ......................146  
routes, advertising..............................................192  
routing..............................................................172  
internal and external ....................................192  
Routing Information Protocol. See RIP  
authentication............................................. 199  
configuration examples........................205 to ??  
default route............................................... 197  
external routes............................................ 203  
filtering criteria........................................... 126  
host routes ................................................. 202  
link state database....................................... 191  
neighbors................................................... 191  
overview.................................................... 188  
redistributing routes ............................ 174, 179  
route maps ......................................... 174, 176  
route summarization.................................... 196  
router ID.................................................... 199  
virtual link ................................................. 198  
outgoing route maps .......................................... 175  
P
password  
administrator account .................................... 47  
default......................................................... 47  
user account................................................. 47  
Per Hop Behavior (PHB).................................... 134  
port mirroring ................................................... 246  
configuration rules ........................................ 96  
Port Trunking...................................................... 95  
port trunking....................................................... 95  
configuration example................................... 97  
description ................................................... 99  
EtherChannel ............................................... 94  
fault tolerance............................................... 95  
ports  
for services ................................................ 127  
monitoring ................................................. 246  
physical. See switch ports.  
RSA keys............................................................59  
RSTP................................................................118  
priority value (802.1p) ....................................... 139  
protocol types ................................................... 126  
PVID (port VLAN ID)......................................... 77  
PVLAN.............................................................. 87  
S
SecurID ..............................................................60  
security  
LDAP authentication .....................................53  
port mirroring .............................................246  
RADIUS authentication .................................44  
VLANs........................................................75  
segmentation. See IP subnets.  
42C4911, January 2007  
Index 259  
 
Alteon OS Application Guide  
segments. See IP subnets.  
U
service ports ......................................................127  
SNMP.........................................................36, 193  
HP-OpenView ..............................................36  
spanning tree  
UDP................................................................. 126  
jumbo frame traffic fragmentation................. 147  
user account........................................................ 47  
configuration rules.........................................96  
Spanning-Tree Protocol  
multiple instances ........................................111  
SSH  
V
virtual interface router (VIR) .............................. 224  
virtual link, OSPF.............................................. 198  
Virtual Local Area Networks. See VLANs.  
virtual router  
ID numbering............................................. 231  
virtual router group............................................ 229  
Virtual Router Redundancy Protocol  
RSA host and server keys ...............................59  
SSH/SCP  
configuring ...................................................56  
statistical load distribution.....................................95  
summarizing routes ............................................196  
switch failover ...................................................227  
switch ports VLANs membership ..........................79  
tracking ..................................................... 230  
VLANs  
broadcast domains................................. 75, 150  
configuration rules ........................................ 96  
default PVID................................................ 77  
example showing multiple VLANs ................. 85  
ID numbers .................................................. 77  
IP interface configuration............................. 151  
multiple spanning trees ................................ 106  
multiple VLANs ........................................... 80  
port members ............................................... 79  
PVID........................................................... 77  
routing....................................................... 150  
security........................................................ 75  
Spanning-Tree Protocol ............................... 106  
tagging ............................................... 79 to 86  
topologies .................................................... 84  
VRRP (Virtual Router Redundancy Protocol)  
active-active redundancy.............................. 228  
hot-standby redundancy............................... 229  
overview............................................ 224, 230  
virtual interface router ................................. 224  
virtual router ID numbering.......................... 231  
vrid ........................................................... 224  
T
TACACS+ ..........................................................48  
tagging. See VLANs tagging.  
TCP ..................................................................126  
technical terms  
port VLAN identifier (PVID)..........................80  
tagged frame.................................................80  
tagged member..............................................80  
untagged frame..............................................80  
untagged member ..........................................80  
VLAN identifier (VID) ..................................80  
text conventions...................................................18  
thash .................................................................100  
Trunk Hash algorithm.........................................100  
Trunking  
configuration rules.........................................96  
typographic conventions .......................................18  
260 Index  
42C4911, January 2007  
 

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