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6-12
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-09
Chapter 6 Clustering Switches
Planning a Switch Cluster
Figure 6-8
Discovery of Newly Installed Switches
HSRP and Standby Command Switches
The switch supports Hot Standby Router Protocol (HSRP) so that you can configure a group of standby
command switches. Because a command switch manages the forwarding of all communication and
configuration information to all the member switches, we strongly recommend that you configure a
cluster standby command switch to take over if the primary command switch fails.
A cluster standby group is a group of command-capable switches that meet the requirements described
in the
“Standby Command Switch Characteristics” section on page 6-3
. Only one cluster standby group
can be assigned per cluster. Follow these guidelines when configuring a cluster standby group:
•
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.
•
When the command switch is running Cisco IOS Release 12.0(5)WC2 or earlier, the standby
command switches can be these switches: Catalyst 2900 XL, non-LRE Catalyst 2950, and
Catalyst 3500 XL switches.
Note
The cluster standby group is an HSRP group. Disabling HSRP disables the cluster standby group.
Si
Si
Command switch
New (out-of-box)
Catalyst 2950
switch
AP
Catalyst 2950
switch
VLAN 9
VLAN 9
VLAN 16
VLAN 16
New (out-of-box)
Catalyst 3550
switch
Catalyst 3500 XL
switch
65278
AP
(Management
VLAN 9)
(Management
VLAN 16)