Configuration - Cisco Catalyst 2000 Configuration Handbook

132 Cisco LAN Switching Configuration Handbook
The following events cause a switchover:
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Configuration

Enter router redundancy configuration mode.
1.
(global) redundancy
This places the switch into redundancy configuration mode so that redundancy can
be enabled.
Select route processor redundancy.
2.
(redundancy) mode rpr | rpr-plus
This enables route processor redundancy mode. During normal operation, the start-
up-config and config-registers configuration are synchronized by default between
the two Supervisor engines. In a switchover, the new active Supervisor engine uses
the current configuration.
Save configuration.
3.
(exec) copy running-configuration startup-configuration
Displaying Information About RPR
To show the status of RPR, enter the following command:
(exec) show redundancy states
8-2: Non-Stop Forwarding/Supervisor Switchover
(NSF/SSO) with Supervisor Redundancy
Cisco NSF works with SSO to minimize the amount of time a network is unavailable to
its users following a switchover while continuing to forward IP packets.
SSO establishes one of the Supervisor engines as active while the other Supervisor engine
is designated as standby, and then SSO synchronizes information between them. A
switchover from the active to the redundant Supervisor engine occurs when the active
Supervisor engine fails, is removed from the switch, or is manually shut down for mainte-
nance. This type of switchover ensures that Layer 2 traffic is not interrupted. In network-
ing devices running SSO, both Supervisor engines must be running the same configura-
tion so that the redundant Supervisor engine is always ready to assume control following
a fault on the active Supervisor engine.
A hardware failure on the active Supervisor engine
Clock synchronization failure between Supervisor engines
A manual switchover