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Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
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Chapter7 Clustering Switches Planning a Switch Cluster
Discovery through Different Management VLANs
We recommend using as a command switch a Catalyst 3550 switch, a Catalyst 2955 switch, a
Catalyst 2950 LRE switch, a non-LRE Catalyst 2950 switch running Cisco IOS Release 12.1(9)EA1 or
later, or a Catalyst 2940 switch. These command switches can discover and manage member switches in
different VLANs and different management VLANs. As clust er me mb er sw it ch es, t hey must be
connected through at least one VLAN in common with the cluster command switch. They do not need
to be connected to the cluster command switch through t he ir m ana gem ent VL AN. Al l ot her m embe r
switches must be connected to the command switch through thei r m ana geme nt V LAN .
In contrast, a Catalyst 2900 XL command switch, a non-LRE Catalyst 2950 command switch running a
release earlier than Cisco IOS Release12.1(9)EA1, or a Catalyst 3500 XL command switch must
connect to all cluster members through its management VLAN. T he d efau lt ma na geme nt VLA N i s
VLAN 1. For information about discovery through the same managem ent VL AN o n th ese switc hes, see
the “Discovery through the Same Management VLAN” section on page 7-8.
The cluster command switch and standby command switch in Figure7-5 (assuming they are
recommended command and standby switches) have ports assigned to VLANs 9, 16, and 62. The
management VLAN on the cluster command switch is VLAN 9. Each cluster command switch discovers
the switches in the different management VLANs except these:
Switches 7 and 10 (switches in management VLAN 4) because they are not connected throu gh a
common VLAN (meaning VLANs 62 and 9) with the cluster command switch
Switch 9 because automatic discovery does not extend beyond a noncandidate device, which is
switch 7
Figure7-5 Discovery through Different Management VLANs
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VLAN 62
VLAN trunk 4, 62
VLAN 62
VLAN 16
VLAN 9
VLAN 16 VLAN 9
Standby command
switch
Command
switch
VLAN 9
Switch 7
(management
VLAN 4)
Switch 9
(management
VLAN 62)
VLAN 4
Switch 3
(management
VLAN 16)
Switch 4
(management
VLAN 16)
Switch 10
(management
VLAN 4)
Switch 8
(management
VLAN 9)
Switch 6
(management
VLAN 9)
Switch 5
(management
VLAN 62)