Virtual Ip Addresses; Other Considerations For Cluster Standby Groups - Cisco 2950 - Catalyst Switch Configuration Manual

Planning a Switch Cluster
standby priority interface configuration command in the Cisco IOS Release 12.1 documentation set.
The HSRP commands are the same for changing the priority of cluster standby group members and
router-redundancy group members.
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 10 seconds. The default HSRP standby hello time
interval is 3 seconds. For more information about the standby hold time and hello time intervals, refer
to the Cisco IOS Release 12.1 documentation set on Cisco.com.
These connectivity guidelines ensure automatic discovery of the switch cluster, cluster candidates,
connected switch clusters, and neighboring edge devices. These topics also provide more detail about
standby command switches:
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•
•

Virtual IP Addresses

You need to assign a unique virtual IP address and group number and name to the cluster standby group.
This information must be configured on the management VLAN on the active command switch. The
active command switch receives traffic destined for the virtual IP address. To manage the cluster, you
must access the active command switch through the virtual IP address, not through the command-switch
IP address. This is in case the IP address of the active command switch is different from the virtual IP
address of the cluster standby group.
If the active command switch fails, the standby command switch assumes ownership of the virtual IP
address and becomes the active command switch. The passive switches in the cluster standby group
compare their assigned priorities to determine the new standby command switch. The passive standby
switch with the highest priority then becomes the standby command switch. When the previously active
command switch becomes active again, it resumes its role as the active command switch, and the current
active command switch becomes the standby command switch again. For more information about IP
address in switch clusters, see the

Other Considerations for Cluster Standby Groups

These requirements also apply:
•
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
7-12
Virtual IP Addresses, page 7-12
Other Considerations for Cluster Standby Groups, page 7-12
Automatic Recovery of Cluster Configuration, page 7-14
Standby command switches must meet these requirements:
When the command switch is a Catalyst 3550 switch, all standby command switches must be
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Catalyst 3550 switches.
When the command switch is a Catalyst 2955 switch, all standby command switches must be
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Catalyst 2955 switches.
When the command switch is a Catalyst 2950 LRE switch, all standby command switches must
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be Catalyst 2950 LRE switches.
"IP Addresses" section on page
Chapter 7 Clustering Switches
7-14.
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