Understanding Switch Clusters - Cisco Catalyst 3750-X Software Configuration Manual

Understanding Switch Clusters

Understanding Switch Clusters
A switch cluster is a set of up to 16 connected, cluster-capable Catalyst switches that are managed as a
single entity. The switches in the cluster use the switch clustering technology so that you can configure
and troubleshoot a group of different Catalyst desktop switch platforms through a single IP address.
In a switch cluster, 1 switch must be the cluster command switch and up to 15 other switches can be
cluster member switches. The total number of switches in a cluster cannot exceed 16 switches. The
cluster command switch is the single point of access used to configure, manage, and monitor the cluster
member switches. Cluster members can belong to only one cluster at a time.
A switch cluster is different from a switch stack. A switch stack is a set of Catalyst 3750-X,
Note
Catalyst 3750-E, or Catalyst 3750 switches connected through their stack ports. For more information
about how switch stacks differ from switch clusters, see the
on page
The benefits of clustering switches include:
•
•
•
Table 6-1
command switches and which ones can only be cluster member switches, and the required software
versions.
Table 6-1
Switch
Catalyst 3750-X
Catalyst 3750-E
Catalyst 3750
Catalyst 3560-X
Catalyst 3560-E
Catalyst 3560
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
6-2
6-14.
Management of Catalyst switches regardless of their interconnection media and their physical
locations. The switches can be in the same location, or they can be distributed across a Layer 2 or
Layer 3 (if your cluster is using a Catalyst 3560, Catalyst 3750, Catalyst 3560-E, Catalyst 3750-E,
Catalyst 3560-X, or Catalyst 3750-X switch as a Layer 3 router between the Layer 2 switches in the
cluster) network.
Cluster members are connected to the cluster command switch according to the connectivity
guidelines described in the
page 6-5. This section includes management VLAN considerations for the Catalyst 1900,
Catalyst 2820, Catalyst 2900 XL, Catalyst 2950, and Catalyst 3500 XL switches. For complete
information about these switches in a switch-cluster environment, see the software configuration
guide for that specific switch.
Command-switch redundancy if a cluster command switch fails. One or more switches can be
designated as standby cluster command switches to avoid loss of contact with cluster members. A
cluster standby group is a group of standby cluster command switches.
Management of a variety of Catalyst switches through a single IP address. This conserves on IP
addresses, especially if you have a limited number of them. All communication with the switch
cluster is through the cluster command switch IP address.
lists the Catalyst switches eligible for switch clustering, including which ones can be cluster
Switch Software and Cluster Capability
"Automatic Discovery of Cluster Candidates and Members" section on
Cisco IOS Release
12.2(53)SE2 or later
12.2(35)SE2 or later
12.1(11)AX or later
12.2(53)SE1 or later
12.2(35)SE2 or later
12.1(19)EA1b or later
Chapter 6
"Switch Clusters and Switch Stacks" section
Cluster Capability
Member or command switch
Member or command switch
Member or command switch
Member or command switch
Member or command switch
Member or command switch
Clustering Switches
OL-21521-01