Configuring switch redundancy & clustering – Brocade Mobility RFS7000-GR Controller System Reference Guide (Supporting software release 4.1.0.0-040GR and later) User Manual

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Brocade Mobility RFS7000-GR Controller System Reference Guide

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Configuring switch redundancy & clustering

Configuration and network monitoring are two tasks a network administrator faces as a network
grows in terms of the number of managed nodes (switches, routers, wireless devices etc.). Such
scalability requirements lead network administrators to look for managing and monitoring each
node from a single centralized management entity. The switch not only provides a centralized
management solution, it provides centralized management from any single switch in the network
without restricting or dedicating one switch as a centralized management node. This eliminates
dedicating a management entity to manage all redundancy members and eliminates the possibility
of a single point of failure.

A redundancy group (cluster) is a set of switches (nodes) uniquely identified by group/cluster ID.
Within the redundancy group, members discover and establish connections to other group
members. The redundancy group has full mesh connectivity using TCP as the transport layer
connection.

Up to 12 switches can be configured as members of a redundancy group to significantly reduce the
chance of a disruption in service to WLANs and associated MUs in the event of failure of a switch or
intermediate network failure. All members can be configured using a common file (cluster-config)
using DHCP options. This functionality provides an alternative method for configuring members
collectively from a centralized location, instead of configuring specific redundancy parameters on
individual switches.

Configure each switch in the cluster by logging in to one participating switch. The administrator
does not need to login to each redundancy group member, as one predicating switch can configure
each member in real-time without “pushing” configurations between switches. A new CLI context
called "cluster-cli" is available to set the configuration for all members of the cluster. All switch CLI
commands are considered cluster configurable.

In the following example, there are four switches (WS1, WS2, WS3 and WS4) forming a redundancy
group. Each switch has established a TCP connection with the others in the group. There is an
additional CLI context called cluster-context. A user/administrator can get into this context by
executing a "cluster-cli enable" under the CLI interface (future releases will have this support in the
Web UI and SNMP interfaces). When the user executes this command on WS1, WS1 creates a
virtual session with the other switches in the redundancy group (WS2, WS3 and WS4). Once the
virtual session is created, any command executed on WS1 is executed on the other switches at the
same time. This is done by the cluster-protocol running on WS1, by duplicating the commands and
sending them to the group over the virtual connection: