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Catalyst 2940 Switch Software Configuration Guide
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Chapter5 Clustering Switches
Understanding Switch Clusters
Cluster members are connected to the command switch according to the connectivity guidelines
described in the “Automatic Discovery of Cluster Candidates and Members” section on page 5-3.
Command-switch redundancy if a command switch fails. One or more s witc he s can be de signat ed
as standby command switches to avoid loss of contact with cluster members. A cluster standby group
is a group of standby command switches.
Management of a variety of Catalyst switches through a single IP address. This co nserves o n IP
addresses, especially if you have a limited number of them. All communication with the switch
cluster is through the command switch IP address.
For other clustering benefits, see the “Advantages of Using CMS and Clustering Switches” section on
page 1-6.
Refer to the switch release notes for a list of Catalyst switches eligible for switch clustering, including
possible command switches and member switches and the requ ired softwar e version s.
These sections describe:
Command Switch Characteristics, page 5-2
Standby Command Switch Characteristics, page 5-2
Candidate Switch and Member Switch Characteristics, page 5-3
Command Switch Characteristics
A Catalyst 2940 command switch must meet these requirements:
It is running Cisco IOS Release 12.1(13)AY or later.
It has an IP address.
It has Cisco Discovery Protocol (CDP) version 2 enabled (the default).
It is not a command or member switch of another cluster.
Note We strongly recommend that the highest-end, command-capable switch in the cluster be the command
switch.
Standby Command Switch Characteristics
A Catalyst 2940 standby command switch must meet these requireme nts:
It is running Cisco IOS Release 12.1(13)AY or later.
It has an IP address.
It has CDP version 2 enabled.
It is redundantly connected to the cluster so that connectivity to member switches is maintained.
It is not a command or member switch of another cluster.
We strongly recommend that the command switch and standby command switches are of the same
switch platform—if you have a Catalyst 2940 command switch, the standby command switches
should be Catalyst 2940 switches.