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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter5 Clustering Switches
Planning a Switch Cluster
Planning a Switch Cluster
Anticipating conflicts and compatibility issues is a high priority when you manage several switches
through a cluster. This section describes these guidelines, requirements, a nd cave ats tha t yo u s hould
understand before you create the cluster:
Automatic Discovery of Cluster Candidates and Members, page 5-4
HSRP and Standby Command Switches, page 5-12
IP Addresses, page 5-15
Host Names, page 5-16
Passwords, page 5-16
SNMP Community Strings, page 5-16
TACACS+, page 5-17
Access Modes in CMS, page 5-17
LRE Profiles, page 5-17
Availability of Switch-Specific Features in Switch Clusters, page 5-18
Refer to the release notes for the list of Catalyst switches eligible for switch clustering, including which
ones can be command switches and which ones can only be member switches, and for the required
software versions and browser and Java plug-in configurations.

Automatic Discovery of Cluster Candidates and Members

The command switch uses Cisco Discovery Protocol (CDP) t o d iscov er mem be r sw itche s, c andi date
switches, neighboring switch clusters, and edge devices across multiple VLAN s and in star or cascaded
topologies.
Note Do not disable CDP on the command switch, on cluster members, or on any cluster- capabl e switches
that you might want a command switch to discover. For more information about CDP, see Chapter 13,
“Configuring CDP.”
Following these connectivity guidelines ensures automatic discovery of the switch cluster, cluster
candidates, connected switch clusters, and neighboring e dge d ev ices :
Discovery through CDP Hops, page 5-5
Discovery through Non-CDP-Capable and Noncluster-Capable Devices, page 5-6
Discovery through Different VLANs, page 5-7
Discovery through Different Management VLANs, page 5-9
Discovery through the Same Management VLAN, page 5-8
Discovery through Routed Ports, page 5-10
Discovery of Newly Installed Switches, page 5-11