6-4
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 6 Clustering Switches
Planning a Switch Cluster
Note Non-LRE Catalyst 2950 command switches running Cisco IOS Release 12.1(9)EA1 or later
can connect to standby command switches in the management VLAN.
• It is redundantly connected to the cluster so that connectivity to member switches is maintained.
• It is not a command or member switch of another cluster.
Note Standby cluster command switches must be the same type of switches as the cluster
command switch. For example, if the cluster command switch is a Catalyst 2955 switch, the
standby cluster command switches must also be Catalyst 2955 switches. When the command
switch is a non-LRE Catalyst 2950 switch running Cisco IOS Release 12.1(6)EA2 or later,
all standby command switches must be non-LRE Catalyst 2950 switches running Cisco IOS
Release 12.1(6)EA2 or later.

Candidate Switch and Member Switch Characteristics

Candidate switches are cluster-capable switches that have not yet been added to a cluster. Cluster
member switches are switches that have actually been added to a switch cluster. Although not required,
a candidate or cluster member switch can have its own IP address and password.
To join a cluster, a candidate switch must meet these requirements:
• It is running cluster-capable software.
• It has CDP Version 2 enabled.
• It is not a command or member switch of another cluster.
• A Catalyst 2950 LRE or Catalyst 2955 member or candidate switch is connected to the command
switch through at least one common VLAN.
• If a non-LRE Catalyst 2950 member or candidate switch is running Cisco IOS Release 12.1(9)EA1
or later, it is connected to the command switch through at least one common VLAN.
• If a non-LRE Catalyst 2950 member or candidate switch is running a release earlier than Cisco IOS
Release 12.1(9)EA1, it is connected to the command switch through the command-switch
management VLAN.
Note Non-LRE Catalyst 2950 standby command switches running Cisco IOS Release 12.1(9)EA1
or later can connect to candidate and member switches in VLANs different from their
management VLANs.
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, and caveats that you should
understand before you create the cluster:
• Automatic Discovery of Cluster Candidates and Members, page 6-5
• HSRP and Standby Cluster Command Switches, page 6-9