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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 51 Troubleshooting Recovering from a Command Switch Failure
Recovering from a Command Switch Failure
This section describes how to recover from a failed command switch. You can configure a redundant
command switch group by using the Hot Standby Router Protocol (HSRP). For more information, see
Chapter 6, “Clustering Switches.”For more information, see Chapter 6, “Clustering Switches” and
Chapter 44, “Configuring HSRP.” Also see the Getting Started with Cisco Network Assistant, available
on Cisco.com.
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, through the Ethernet management port, or, if they have IP addresses, through
the other management interfaces.
You can prepare for a command switch failure by assigning an IP address to a member switch or another
switch that is command-capable, making a note of the command-switch password, and cabling your
cluster to provide redundant connectivity between the member switches and the replacement command
switch. These sections describe two solutions for replacing a failed command switch:
• Replacing a Failed Command Switch with a Cluster Member, page 51-9
• Replacing a Failed Command Switch with Another Switch, page 51-11
These recovery procedures require that you have physical access to the switch.
For information on command-capable switches, see the release notes.

Replacing a Failed Command Switch with a Cluster Member

To replace a failed command switch with a command-capable member in the same cluster, 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, by using the Ethernet management port, or, if an IP
address has been assigned to the switch, by using Telnet. For details about using the console port, see
the switch hardware installation guide. For details about using the Ethernet management port, see the
“Using the Ethernet Management Port” section on page 13-22 and the 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.