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Catalyst 3750-E and 3560-E Switch Software Configuration Guide
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Chapter6 Clustering Switches
Planning a Switch Cluster
Automatic Discovery of Cluster Candidates and Members
The cluster command switch uses Cisco Discovery Protocol (CDP) to discover cluster member switches,
candidate switches, neighboring switch clusters, and edge devices across multiple VLANs an d in star or
cascaded topologies.
Note Do not disable CDP on the cluster command switch, on cluster members, or on any cluster-capable
switches that you might want a cluster command switch to discover. For more information about CDP,
see Chapter 27, “Configuring CDP.”
Following these connectivity guidelines ensures automatic discovery of the switch cluster, cluster
candidates, connected switch clusters, and neighboring e dge devices:
•Discovery Through CDP Hops, page 6-5
•Discovery Through Non-CDP-Capable and Noncluster-Capable Devices, page 6-6
•Discovery Through Different VLANs, page 6-7
•Discovery Through Different Management VLANs, page 6-8
•Discovery Through Routed Ports, page 6-9
•Discovery of Newly Installed Switches, page 6-10

Discovery Through CDP Hops

By using CDP, a cluster command switch can discover switches up to sevenCDP hops away (the default
is three hops) from the edge of the cluster. The edge of the cluster is where the last cluster member
switches are connected to the cluster and to candidate switches. For example, cluster member switches9
and 10 in Figure 6-1 are at the edge of the cluster.