Specifications

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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 7 Clustering Switches
Planning a Switch Cluster
• Each standby-group member (Figure 7-9) must be connected to the command switch through its
management VLAN. Each standby-group member must also be redundantly connected to each other
through the management VLAN.
Catalyst 1900, Catalyst 2820, Catalyst 2900 XL, Catalyst 2950, Catalyst 2955, and
Catalyst 3500 XL member switches must be connected to the cluster standby group through their
management VLANs.
Note Catalyst 2950 standby command switches running Release 12.1(9)EA1 or later can connect to candidate
and member switches in VLANs different from their management VLANs. Catalyst 2955 standby
command switches running Release 12.1(12c)EA1 or later 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 7-9
– “Discovery through Different Management VLANs” section on page 7-10
Figure 7-9 VLAN Connectivity between Standby-Group Members and Cluster Members
Automatic Recovery of Cluster Configuration
The active command switch continually forwards cluster-configuration information (but not
device-configuration information) to the standby command switch. This ensures that the standby
command switch can take over the cluster immediately after the active command switch fails.
Si
Management
VLAN 16
Catalyst 2900 XL or
Catalyst 3500 XL
switch
Catalyst 3550
multilayer switch
Catalyst 3550 standby
command switch
VLAN 16
VLAN 9
Si Si
VLAN 9
Catalyst 3550 active
command switch
Catalyst 3550 passive
command switch
Member switches
Management
VLAN 9
Catalyst 3550
switch
Catalyst 2950
switch
VLAN 9
VLANs 9,16 VLANs 9,16
Management
VLAN 16
65280
Si