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Software Configuration Guide—Release 12.2(25)SG
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Chapter6 Configuring Supervisor Engine Red undancy Using RPR and SSO
Understanding Supervisor Engine Redundancy
Table 6 -1 lists the supervisor engines and Catalys t 4500 series switches that support NSF-awareness:
In Release 12.2(20)EWA, NSF-awareness is supported on Catalyst 4500 series switches for EIGRP,
IS-IS, OSPF and BGP protocols. NSF-awareness is turned on by default for EIGRP, IS-IS and OSPF
protocols. For BGP, it needs to be turned 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 serie s switch).
Understanding Supervisor Engine Redundancy
These sections describe supervisor engine redundancy:
•Overview, page 6-3
•RPR Operation, page 6-4
•SSO Operation, page 6-4
•“Understanding Supervisor Engine Redundancy Synchronization” section on page 6-6

Overview

With supervisor engine redundancy enabled, if the active supervisor engine fails or if a manual
switchover is performed, the redundant supervisor engine become s the active supervisor engine. The
redundant supervisor engine has been automatically initialized with the startup configuration of the
active supervisor engine, shortening the switchover time (30 seconds or longer in RPR mode, depe nding
on the configuration; subseconds in SSO mode).
In addition to the reduced switchover time, supervisor engine re dundancy supports the following:
•Online insertion and removal (OIR) of the redundant supervisor engine.
Supervisor engine redundancy allows OIR of the redundant supervisor engine for maintenance.
When the redundant supervisor engine is inserted, the active supervisor engine detects its presence ,
and the redundant supervisor engine boots into a partially-initialized state in RPR mode and a
fully-initialized state in SSO mode.
•Software upgrade. (See the “Performing a Software Upgrade” section on page 6-12.)
To minimize down time during software changes on the supervisor engine, load the new ima ge on
the redundant supervisor engine, and conduct a switchover.
Table6-1 NSF-Aware Capable Supervisor Engine and Catalyst 4500 Series Switch Matrix
NSF-Aware Capable Supervisor Engine Switch Support
Supervisor Engine III (WS-X4014) Catalyst 4506 series switch and Catalyst 4503
series switch
Supervisor Engine IV (WS-X4515) Catalyst 4507R series switch, Catalyst 4506
series switch, and Catalyst 4503 series switch
Supervisor Engine V (WS-X4516) Catalyst 4507R series switch and Catalyst 4510R
series switch
Fixed Switch (WS-C4948) Catalyst 4948 switch