Cisco CATALYST 2960

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Catalyst 2960 and 2960-S Switches Software Configuration Guide, Release 15.0(1)SE
OL-26520-01
Chapter 6 Clustering Switches
Planning a Switch Cluster
If a switch received its hostname from the cluster command switch, was removed from a cluster, was
then added to a new cluster, and kept the same member number (such as 5), the switch overwrites the
old hostname (such as eng-cluster-5) with the hostname of the cluster command switch in the new cluster
(such as mkg-cluster-5). If the switch member number changes in the new cluster (such as 3), the switch
retains the previous name (eng-cluster-5).
Passwords
You do not need to assign passwords to an individual switch if it will be a cluster member. When a switch
joins a cluster, it inherits the command-switch password and retains it when it leaves the cluster. If no
command-switch password is configured, the cluster member switch inherits a null password. Cluster
member switches only inherit the command-switch password.
If you change the member-switch password to be different from the command-switch password and save
the change, the switch is not manageable by the cluster command switch until you change the
member-switch password to match the command-switch password. Rebooting the member switch does
not revert the password back to the command-switch password. We recommend that you do not change
the member-switch password after it joins a cluster.
For more information about passwords, see the “Preventing Unauthorized Access to Your Switch”
section on page 9-1.
For password considerations specific to the Catalyst 1900 and Catalyst 2820 switches, refer to the
installation and configuration guides for those switches.
SNMP Community Strings
A cluster member switch inherits the command-switch first read-only (RO) and read-write (RW)
community strings with @esN appended to the community strings:
• command-switch-readonly-community-string@esN, where N is the member-switch number.
• command-switch-readwrite-community-string@esN, where N is the member-switch number.
If the cluster command switch has multiple read-only or read-write community strings, only the first
read-only and read-write strings are propagated to the cluster member switch.
The switches support an unlimited number of community strings and string lengths. For more
information about SNMP and community strings, see Chapter 30, “Configuring SNMP.”
For SNMP considerations specific to the Catalyst 1900 and Catalyst 2820 switches, refer to the
installation and configuration guides specific to those switches.
Switch Clusters and Switch Stacks
A switch cluster can have one or more Catalyst 2960-S switch stacks. Each switch stack can act as the
cluster command switch or as a single cluster member. Table 6-2 describes the basic differences between
switch stacks and switch clusters. For more information about switch stacks, see Chapter 7, “Managing
Switch Stacks.”
Note Stacking is supported only on Catalyst 2960-S switches running the LAN base image.