6-3
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-09
Chapter 6 Clustering Switches
Understanding Switch Clusters
Command Switch Characteristics
A Catalyst 3550 command switch must meet these requirements:
•
It is running Cisco IOS Release 12.1(4)EA1 or later.
•
It has an IP address.
•
It has Cisco Discovery Protocol (CDP) version 2 enabled (the default).
•
It is not a command or member switch of another cluster.
•
It is connected to the standby command switches through the management VLAN and to the member
switches through a common VLAN.
•
We strongly recommend that the highest-end, command-capable switch in the cluster be the
command switch:
–
If your switch cluster has a Catalyst 3550 switch, that switch should be the command switch.
–
If your switch cluster has Catalyst 2900 XL, Catalyst 2940, Catalyst 2950, Catalyst 2955, and
Catalyst 3500 XL switches, the Catalyst 2950 or the Catalyst 2955 should be the command
switch.
–
If your switch cluster has Catalyst 1900, Catalyst 2820, Catalyst 2900 XL, and
Catalyst 3500 XL switches, either the Catalyst 2900 XL or Catalyst 3500 XL should be the
command switch.
Standby Command Switch Characteristics
A Catalyst 3550 standby command switch must meet these requirements:
•
It is running Cisco IOS Release 12.1(4)EA1 or later.
•
It has an IP address.
•
It has CDP version 2 enabled.
•
It is connected to other standby switches through its management VLAN and to all member switches
through a common 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.
•
Standby command switches must meet these requirements:
–
When the command switch is a Catalyst 3550 switch, all standby command switches must be
Catalyst 3550 switches.
–
When the command switch is a Catalyst 2955 switch, all standby command switches must be
Catalyst 2955 switches.
–
When the command switch is a Catalyst 2950 LRE switch, all standby command switches must
be Catalyst 2950 LRE switches.
–
When the command switch is a non-LRE Catalyst 2950 switch running Cisco IOS
Release 12.1(9)EA1 or later, all standby command switches must be non-LRE Catalyst 2950
switches running Cisco IOS Release 12.1(9)EA1 or later.
–
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.