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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 6 Clustering Switches
Understanding Switch Clusters
• It has an IP address.
• It has Cisco Discovery Protocol (CDP) version 2 enabled (the default).
• It is not a command or cluster member switch of another cluster.
• A Catalyst 2955 command switch is connected to the standby cluster command switches through the
management VLAN and to the cluster member switches through a common VLAN.
• A Catalyst 2950 Long-Reach Ethernet (LRE) command switch is connected to the standby
command switches through the management VLAN and to the member switches through a common
VLAN.
• If a non-LRE Catalyst 2950 command switch is running Cisco IOS Release 12.1(9)EA1 or later, it
is connected to the standby command switches through the management VLAN and to the member
switches through a common VLAN.
• If a non-LRE Catalyst 2950 command switch is running a release earlier than Cisco IOS
Release 12.1(9)EA1, it is connected to the standby command switches and member switches
through its management VLAN.
Note The CMP-NAT-ACL access list is created when a device is configured as the command switch.
Configuring any other access list on the switch can restrict access to it and affect the discovery of
member and candidate switches.
We strongly recommend that the highest-end, command-capable switch in the cluster be the command
switch:
• If your switch cluster has a Catalyst 3550 switch, that switch should be the command switch.
• If your switch cluster has Catalyst 2900 XL, Catalyst 2940, Catalyst 2950, Catalyst 2955, and
Catalyst 3500 XL switches, the Catalyst 2950 or the Catalyst 2955 should be the command switch
Standby Cluster Command Switch Characteristics
A standby cluster command switch must meet these requirements:
• It is running Cisco IOS 12.0(5.2)WC(1)) or later.
• It has an IP address.
• It has CDP version 2 enabled.
• A Catalyst 2955 standby command switch is connected to other standby switches through its
management VLAN and to all member switches through a common VLAN.
• A Catalyst 2950 LRE standby command switch is connected to other standby switches through its
management VLAN and to all member switches through a common VLAN.
• If a non-LRE Catalyst 2950 standby command switch is running Cisco IOS Release 12.1(9)EA1 or
later, it is connected to other standby switches through its management VLAN and to all member
switches through a common VLAN.
• If a non-LRE Catalyst 2950 standby command switch is running a release earlier than Cisco IOS
Release 12.1(9)EA1, it is connected to the command switch and to other standby command switches
and member switches through its management VLAN.