The Nortel SNAS 35Nortel SNAS clustersFor Release 1.6.1A cluster is a group of Nortel SNAS 4050 devices that share the sameconfiguration parameters. Nortel Secure Network Access Switch SoftwareRelease 1.6.1 supports four Nortel SNAS 4050 devices, or nodes, in acluster. A network can contain multiple clusters.For Release 2.0A cluster is a group of Nortel SNAS 4050 or 4070 devices that share thesame configuration parameters. Nortel Secure Network Access SwitchSoftware Release 2.0 supports a combination of four Nortel SNAS 4050and 4070 devices, or nodes, in a cluster. A Nortel SNAS network cancontain multiple clusters.Clustering offers the following benefits:• manageability—The cluster is a single, seamless unit that automaticallypushes configuration changes to its members.• scalability—The Nortel SNAS nodes in a cluster share the burdenof resource-intensive operations. The cluster distributes control ofthe network access devices between the Nortel SNAS nodes anddistributes handling of session logon. As a result, Nortel SNAS devicesin a cluster can control more switches and handle more user sessions.• fault tolerance—If a Nortel SNAS device fails, the failure is detected bythe other node in the cluster, which takes over the switch control andsession handling functions of the failed device. As long as there is onerunning Nortel SNAS, no sessions will be lost.The devices in the cluster can be located anywhere in the network anddo not have to be physically connected to each other. All the NortelSNAS devices in the cluster must be in the same subnet. The cluster iscreated during initial setup of the second node, when you specify thatthe setup is a join operation and you associate the node with an existingManagement IP address (MIP).For more information about Nortel SNAS IP addresses, see “About the IPaddresses” (page 42). For information about adding a node to a cluster,see “Adding a Nortel SNAS device to a cluster” (page 50).Interface configurationThe Nortel SNAS must interface to two kinds of traffic: client andmanagement. The interface to the client side handles traffic between theNortel Health Agent applet on the client and the portal. The interface toNortel Secure Network Access SwitchUsing the Command Line InterfaceNN47230-100 03.01 Standard28 July 2008Copyright © 2007, 2008 Nortel Networks.
