Cisco 3560G 48TS Software Configuration Guide - Page 100

Understanding Switch Clusters

Page 100 highlights

Understanding Switch Clusters Chapter 5 Clustering Switches 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. The benefits of clustering switches include: • 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 3550, Catalyst 3560, or Catalyst 3750 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 "Automatic Discovery of Cluster Candidates and Members" section on page 5-5. 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, refer to 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. Refer to the release notes for the list of Catalyst switches eligible for switch clustering, including which ones can be cluster command switches and which ones can only be cluster member switches, and the required software versions. These sections describe: • Cluster Command Switch Characteristics, page 5-3 • Standby Cluster Command Switch Characteristics, page 5-3 • Candidate Switch and Cluster Member Switch Characteristics, page 5-4 Catalyst 3560 Switch Software Configuration Guide 5-2 78-16156-01

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5-2
Catalyst 3560 Switch Software Configuration Guide
78-16156-01
Chapter 5
Clustering Switches
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.
The benefits of clustering switches include:
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
3550, Catalyst
3560, or Catalyst
3750 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
“Automatic Discovery of Cluster Candidates and Members” section on
page 5-5
. 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, refer to 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.
Refer to the release notes for the list of Catalyst switches eligible for switch clustering, including which
ones can be cluster command switches and which ones can only be cluster member switches, and the
required software versions.
These sections describe:
Cluster Command Switch Characteristics, page 5-3
Standby Cluster Command Switch Characteristics, page 5-3
Candidate Switch and Cluster Member Switch Characteristics, page 5-4