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Cisco Catalyst Switch Module 3110 and 3012 for IBM BladeCenter Software Configuration Guide
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Chapter 38 Configuring IP Unicast Routing
Configuring EIGRP
This feature cannot be disabled. For more information on this feature, see the “EIGRP Nonstop
Forwarding (NSF) Awareness” section of the Cisco IOS IP Routing Protocols Configuration Guide,
Release 12.4 at this URL:
http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a00804529
72.html
EIGRP NSF Capability
The IP-services feature set also supports EIGRP NSF-capable routing for IPv4 for better convergence
and lower traffic loss following a stack-master change. When an EIGRP NSF-capable stack master
restarts or a new stack master starts and NSF restarts, the switch has no neighbors, and the topology table
is empty. The switch must bring up the interfaces, re-acquire neighbors, and rebuild the topology and
routing tables without interrupting the traffic directed to the switch stack. EIGRP peer routers maintain
the routes learned from the new stack master and continue to forward traffic through the NSF restart
process.
To prevent an adjacency reset by the neighbors, the new stack master uses a new restart bit in the EIGRP
packet header. When the neighbor receives it, it synchronizes the stack in its peer list and maintains the
adjacency with the stack. The neighbor then sends its topology table to the stack master with the restart
bit set to show that it is NSF-aware and is aiding the new stack master.
If at least one of the stack peer neighbors is NSF-aware, the stack master receives updates and rebuilds
its database. Each NSF-aware neighbor sends an end-of-table (EOT) marker in the last update packet to
mark the end of the table content. The stack master recognizes the convergence when it receives the EOT
marker and begins sending updates. When the stack master has received all EOT markers from its
neighbors or when the NSF converge timer expires, EIGRP notifies the routing information database
(RIB) of convergence and floods its topology table to all NSF-aware peers.
Note NSF is not supported on interfaces configured for Hot Standby Router Protocol (HSRP).
Use the nsf EIGRP routing configuration command to enable EIGRP NSF routing. Use the show ip
protocols privileged EXEC command to verify that NSF is enabled. See the command reference for this
release for information about the nsf command.
Configuring Basic EIGRP Parameters
Beginning in privileged EXEC mode, follow these steps to configure EIGRP. Configuring the routing
process is required; other steps are optional:
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
router eigrp autonomous-system Enable an EIGRP routing process, and enter router configuration
mode. The autonomous-system number identifies the routes to
other EIGRP routers and tags routing information.
Step 3
nsf (Optional) Enable EIGRP NSF. Enter this command on the stack
master and on all of its peers.
Step 4
network network-number Associate networks with an EIGRP routing process. EIGRP sends
updates to the interfaces in the specified networks.
