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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter5 Clustering Switches Understanding Switch Clusters
Standby Command Switch Characteristics
A Catalyst 3550 standby command switch must meet these requirements:
•It is running 12.1(4)EA1 or later.
•It has an IP address.
•It has CDP version 2 enabled.
•It is connected to the command switch and all other standby command switches thro ugh at least one
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.
Note • When the command switch is a Catalyst3550 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 R ele ase 12.0(5)WC 2 o r
earlier: Catalyst2900 XL, Catalyst 2950, and Catalyst 3500 XL switches.
Candidate and Member Switches Characteristics
Candidate switches are cluster-capable switches that have not yet been added to a cluster. Member
switches are switches that have actually been added to a switch cluster. Although not required, a
candidate or member switch can have its own IP address and password (for related considerations, see
the “IP Addresses” section on page5-15 and “Passwords” section on page 5-16).
To join a cluster, a candidate switch must meet these requirements:
•It is running cluster-capable software.
•It has CDP version 2 enabled.
•It is not a command or member switch of another cluster.
•It is connected to the command switch through at least one common VLAN.
•(If a cluster standby group exists) It is connected to every sta ndby command switch through at least
one common VLAN. The VLAN to each standby command switch can be different.
Note Catalyst 190 0, Catalyst 2820, Cat alyst 2900 XL, Catalyst 2950, and Catalyst 3500 XL
member switches must be connected through their management VLAN to the command
switch and standby command switches. This requirement does not apply to Catalyst 3550
switches, which can connect to any VLAN in common with the command switch.