6-8
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 6 Clustering Switches
Planning a Switch Cluster
Switch 9 because automatic discovery does not extend beyond a noncandidate device, which is
switch 7
Figure 6-4 Discovery Through Different Management VLANs with a Layer 3 Cluster Command
Switch
Discovery of Newly Installed Switches
To join a cluster, the new, out-of-the-box switch must be connected to the cluster through one of its
access ports. An access port (AP) carries the traffic of and belongs to only one VLAN. By default, the
new switch and its access ports are assigned to VLAN 1.
When the new switch joins a cluster, its default VLAN changes to the VLAN of the immediately
upstream neighbor. The new switch also configures its access port to belong to the VLAN of the
immediately upstream neighbor.
The cluster command switch in Figure 6-5 belongs to VLANs 9 and 16. When new cluster-capable
switches join the cluster:
One cluster-capable switch and its access port are assigned to VLAN 9.
The other cluster-capable switch and its access port are assigned to management VLAN 16.
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VLAN 62
VLAN trunk 4, 62
VLAN 62
VLAN 16
VLAN 9
VLAN 16 VLAN 9
Standby command
device
Command
device
VLAN 9
Device 7
(management
VLAN 4)
Device 9
(management
VLAN 62)
VLAN 4
Device 3
(management
VLAN 16)
Device 4
(management
VLAN 16)
Device 10
(management
VLAN 4)
Device 8
(management
VLAN 9)
Device 6
(management
VLAN 9)
Device 5
(management
VLAN 62)