Cisco Catalyst 4500 Series, Software Configuration Manual

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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 13 Configuring Cisco NSF with SSO Supervisor Engine Redundancy
About NSF with SSO Supervisor Engine Redundancy
Table 13-1 lists the supervisor engines and Catalyst 4500 series switches that support NSF-awareness:
Starting with Cisco IOS Release 12.2(20)EWA, the Catalyst 4500 series switch supported
NSF-awareness for the EIGRP, IS-IS, OSPF, and BGP protocols. Starting with Cisco IOS Release
12.2(31)SG, the Catalyst 4500 series switch supported NSF-awareness for the EIGRP-stub in IP Base
image for all supervisor engines. NSF-awareness is turned on by default for EIGRP-stub, EIGRP, IS-IS,
and OSPF protocols. You need to turn BGP on manually.
If the supervisor engine is configured for BGP (with the graceful-restart command), EIGRP, OSPF, or
IS-IS routing protocols, routing updates are automatically sent during the supervisor engine switchover
of a neighboring NSF-capable switch (typically a Catalyst 6500 series switch).
Starting with Cisco IOS Release 12.2(31)SG, the Catalyst 4500 series switch supports NSF-capability.
Table 13-2 lists the supervisor engines and the associated Catalyst 4500 series switches that are
NSF-capable.
NSF with SSO Supervisor Engine Redundancy Overview
Catalyst 4500 series switch support fault resistance by allowing a redundant supervisor engine to take
over if the primary supervisor engine fails. NSF works with SSO to minimize the amount of time a
network is unavailable to its users following a switchover.
NSF provides these benefits:
•
Improved network availability
NSF continues forwarding network traffic and application state information so that user session
information is maintained after a switchover.
•
Overall network stability
Network stability may be improved with the reduction in the number of route flaps, which were
created when routers in the network failed and lost their routing tables.
•
Neighboring routers do not detect a link flap
Because the interfaces remain up during a switchover, neighboring routers do not detect a link flap
(the link does not go down and come back up).
•
Prevents routing flaps
Table 13-1 NSF-Aware Supervisor Engines
NSF-Aware Supervisor Engine Switch Support
Fixed Switch (WS-C4948) Catalyst 4948
Fixed Switch (WS-C4948-10GE) Catalyst 4948-10GE switch
Table 13-2 NSF-Capable Supervisor Engines
NSF-Capable Supervisor Engines Switch Support
Supervisor Engine 6-E (WS-X45-Sup6-E)
Supervisor Engine 6L-E (WS-X45-Sup6L-E) Catalyst 4500 E-series switch
Supervisor Engine 7-E (WS-X45-SUP7-E),
Supervisor Engine 7L-E (WS-X45-SUP7L-E),
and Supervisor Engine 8-E (WS-X45-SUP8-E) WS-C4507R-E, WS-C4510R-E, WS-E,
WS-E