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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter27 Troubleshooting Using Recovery Procedures
Recovering from a Command Switch Failure
This section describes how to recover from a failed command sw itch. You can configure a redu nda nt
command switch group by using the Hot Standby Router Protocol (HSRP). For more information, see
Chapter 5, “Clustering Switches” and Chapter 23, “Configuring HSRP.”
Note HSRP is the preferred method for supplying redundancy to a cluster.
If you have not configured a standby command switch, and your command switch loses power or fails
in some other way, management contact with the member switches is lost, and you must install a new
command switch. However, connectivity between switches that are still connected is not affected, and
the member switches forward packets as usual. You can manage the members as standalone switches
through the console port or, if they have IP addresses, through th e othe r ma nage me nt int erfa ces.
You can prepare for a command s witch failu re by as signin g an IP addr ess to a memb er sw itch or anot her
switch that is command-capable, making a note of the command-switch password, and cabling your
cluster to provide redundant connectivity between the mem ber switches and the replacement command
switch. This section describes two solutions for replacing a fa iled comm a nd switch :
•Replacing a failed command switch with a cluster member
•Replacing a failed command switch with another switch
For information on command-capable switches, refer to the release notes.

Replacing a Failed Command Switch with a Cluster Member

To replace a failed command switch with a command-capable me mb er i n the s ame cl u st er, follow these
steps:
Step 1 Disconnect the command switch from the member switches, and physically remove it from the cluster.
Step 2 Insert the member switch in place of the failed command switch, and duplicate its connections to the
cluster members.
Step 3 Start a CLI session on the new command switch.
You can access the CLI by using the console port or, if an IP address has been assigned to the switch, by
using Telnet. For details about using the console port, refer to the switch hardware installation guide.
Step 4 At the switch prompt, enter privileged EXEC mode:
Switch> enable
Switch#
Step 5 Enter the password of the failed command switch.
Step 6 Enter global configuration mode.
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Step 7 Remove the member switch from the cluster.
Switch(config)# no cluster commander-address
Step 8 Return to privileged EXEC mode.
Switch(config)# end
Switch#