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6-9
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-09
Chapter 6 Clustering Switches
Planning a Switch Cluster
Discovery through Different Management VLANs
We recommend using a Catalyst 3550 command switch, a Catalyst 2955 command switch, a
Catalyst 2950 LRE command switch, or a non-LRE Catalyst 2950 command switch running Cisco IOS
Release 12.1(9)EA1 or later. These command switches can discover and manage member switches in
different VLANs and different management VLANs. Catalyst 3550 member switches, Catalyst 2955
member switches, Catalyst 2950 LRE member switches, and non-LRE Catalyst 2950 member switches
running Cisco IOS Release 12.1(9)EA1 or later must be connected through at least one VLAN in
common with the command switch. All other member switches must be connected to the command
switch through their management VLAN.
In contrast, a Catalyst 2900 XL command switch, a non-LRE Catalyst 2950 command switch running a
release earlier than Cisco IOS Release 12.1(9)EA1, or a Catalyst 3500 XL command switch must
connect to all cluster members through its management VLAN. The default management VLAN is
VLAN 1. For information about discovery through the same management VLAN on these switches, see
the
“Discovery through the Same Management VLAN” section on page 6-8
.
The non-LRE Catalyst 2950 command switch running Cisco IOS Release 12.1(9)EA1 or later in
and the Catalyst 3550 command switch in
have ports assigned to VLANs 9, 16,
and 62. The management VLAN on the Catalyst 2950 command switch is VLAN 9. Each 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 through a
common VLAN (meaning VLANs 62 and 9) with the command switch
•
Switch 9 because automatic discovery does not extend beyond a noncandidate device, which is
switch 7
Figure 6-5
Discovery through Different Management VLANs with a Layer 2 Command Switch
Catalyst 1900,
Catalyst 2820,
Catalyst 2900 XL,
Catalyst 2950,
Catalyst 2955, and
Catalyst 3500 XL
switches
VLAN 62
VLAN trunk 4, 62
VLAN 62
VLAN 16
(management
VLAN 9)
VLAN 16
VLAN 9
Catalyst 2950
standby command switch
Catalyst 2950
command switch
VLAN 9
Switch 7
(management
VLAN 4)
Switch 9
(management
VLAN 62)
VLAN 4
87332
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)