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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter5 Clustering Switches
Creating a Switch Cluster
Creating a Cluster Standby Group
The cluster standby group members must meet the requirement s descr ibe d in t he “Standby Com mand
Switch Characteristics” section on page5-3 and “HSRP and Standby Command Switches” section on
page 5-12. To create a cluster standby group, select Cluster > Standby Command Switches
(Figure 5-12).
Instead of using CMS to add switches to a standby group and to bind the standby group to a cluster, you
can use the standby ip, standby name, standby priority interface configuration commands and the
cluster standby group global configuration command.
Note • When the command switch is a Catalyst 3550 switch, all standby command switches must be
Catalyst 3550 switches or Catalyst 2950 switches running Cisco IOS Release 12.1(6)EA2 or
later.
•When the command switch is a Catalyst 2950 switch running Cisco IOS Release 12.1(6)EA2 or
later, all standby command switches must be Catalyst 2950 switches running Cisco IOS
Release 12.1(6)EA2 or later.
•When the Catalyst 2950 command switch is running Cisco IOS Release 12.0(5)WC2 or earlier, the
standby command switches can be these switches also running Ci sco IOS Release 12.0(5)WC2 o r
earlier: Catalyst 2900 XL, Catalyst 2950, and Catalyst 3500 XL switches.
These abbreviations are appended to the switch host names in the Standby Command Group list to show
their eligibility or status in the cluster standby group:
•AC—Active command switch
•SC—Standby command switch
•PC—Member of the cluster standby group but not the standby command switch
•HC—Candidate switch that can be added to the cluster standby gro up
•CC—Command switch when HSRP is disabled
You must enter a virtual IP address for the cluster standby group. This address must be in the same subnet
as the IP addresses of the switch. The group number must be uniq ue within the IP subnet. It can be from
0 to255, and th e de fault is 0. Th e g rou p nam e can have u p to 3 1 characters.
The Standby Command Configuration window uses the default values for the preempt and name
commands that you have set by using the CLI. If you use this wi ndow to c r eat e t he H SRP gro up, a ll
switches in the group have the preempt command enabled. You must also provide a name for the group.
Note The HSRP standby hold time interval should be greater than or equal to 3 times the hello time
interval. The default HSRP standby hold time interval is 10seconds. The default HSRP standby hello
time interval is 3seconds. For more information about the standby hold time and hello time intervals,
see the “Configuring HSRP Authentication and Timers” section on page 23-8.