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Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
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Chapter7 Clustering Switches Planning a Switch Cluster
When the command switch is a non-LRE Catalyst 2950 switch running Cisco IOS
Release 12.1(6)EA2 or later, all standby command switches must be non-LRE Catalyst 2950
switches running Cisco IOS Release 12.1(6)EA2 or later.
When the command switch is running Cisco IOS Release 12.0(5)WC2 or earlier, the standby
command switches can be these switches: Catalyst 2900 XL, non-LRE Catalyst 2950, and
Catalyst 3500XL switches.
Only one cluster standby group can be assigned to a cluster.
All standby-group members must be members of the cluster.
Note There is no limit to the number of switches that you can assign as standby command
switches. However, the total number of switches in the cluster—which would include the
active command switch, standby-group members, and member switches—cannot be more
than 16.
Each standby-group member (Figure7-8) must be connected to the command swi tch th rough its
management VLAN. Each standby-group member must also be redundantly c onnected to each other
through the management VLAN.
Catalyst 1900, Catalyst282 0, Catalyst 2900 XL, Catalyst 2940, Catalyst 2950, Catalyst 2955, and
Catalyst 3500XL mem ber sw itche s must b e c onnec ted to the c lust er sta ndby gr oup t hr ough thei r
management VLANs.
Note Non-LRE Catalyst 2950 standby command switches running Cisco IOS Release 12.1(9)EA1 or late r can
connect to candidate and member switches in VLANs different from their management VLANs.
For more information about VLANs in switch clusters, see these sections:
“Discovery through the Same Management VLAN” section on page 7-8
“Discovery through Different Management VLANs” section on page 7-9
Figure7-8 VLAN Connectivity between Standby-Group Members and Cluster Members
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Management
VLAN 16
Standby
command switch
VLAN 16
VLAN 9
VLAN 9
Command
switch Passive
command switch
Member switches
Management
VLAN 9
VLANs 9,16 VLANs 9,16
Management
VLAN 16