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Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
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Chapter7 Clustering Switches
Planning a Switch Cluster
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 the management VLAN. By
default, the new switch and its access ports are assigned to management VLAN1.
When the new switch joins a cluster, its default management 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.
Figure 7-6 shows a non-LRE Catalyst 2950 command switch running a release earlier than Cisco IOS
Release 12.1(9)EA1 that belongs to management VLAN 16. When the new candidate switches join the
cluster, their management VLAN and access ports change from VLAN 1 to VLAN 16.
The command switch in Figure 7-7 is a non-LRE Catalyst 2950 running Cisco IOS Release 12.1(9)EA1
or later, a Catalyst 2950 LRE switch, or a Catalyst 2955 switch that belongs to VLANs 9 and 16. When
the new candidate switches join the cluster:
Switch A and its access port are assigned to management VLAN 9.
Switch B and its access port are assigned to management VLAN16.
Figure7-6 Discovery of Newly Installed Switches in the Same Management VLAN
APAP
Command switch
Switch B
(Management
VLAN 16)
Switch A
(Management
VLAN 16)
VLAN 16
VLAN 16
VLAN 16
VLAN 16
New (out-of-box)
candidate switch New (out-of-box)
candidate switch
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