Cisco 3560G 48TS Software Configuration Guide - Page 111

Chapter 5 Clustering Switches Planning a Switch Cluster When the previously active cluster command switch resumes its active role, it receives a copy of the latest cluster configuration from the active cluster command switch, including members that were added while it was down. The active cluster command switch sends a copy of the cluster configuration to the cluster standby group. IP Addresses You must assign IP information to a cluster command switch. You can assign more than one IP address to the cluster command switch, and you can access the cluster through any of the command-switch IP addresses. If you configure a cluster standby group, you must use the standby-group virtual IP address to manage the cluster from the active cluster command switch. Using the virtual IP address ensures that you retain connectivity to the cluster if the active cluster command switch fails and that a standby cluster command switch becomes the active cluster command switch. If the active cluster command switch fails and the standby cluster command switch takes over, you must either use the standby-group virtual IP address or any of the IP addresses available on the new active cluster command switch to access the cluster. You can assign an IP address to a cluster-capable switch, but it is not necessary. A cluster member switch is managed and communicates with other cluster member switches through the command-switch IP address. If the cluster member switch leaves the cluster and it does not have its own IP address, you then must assign IP information to it to manage it as a standalone switch. Note Changing the cluster command switch IP address ends your CMS session on the switch. Restart your CMS session by entering the new IP address in the browser Location field (Netscape Communicator) or Address field (Internet Explorer), as described in the release notes. For more information about IP addresses, see Chapter 4, "Assigning the Switch IP Address and Default Gateway." Host Names You do not need to assign a host name to either a cluster command switch or an eligible cluster member. However, a host name assigned to the cluster command switch can help to identify the switch cluster. The default host name for the switch is Switch. If a switch joins a cluster and it does not have a host name, the cluster command switch appends a unique member number to its own host name and assigns it sequentially as each switch joins the cluster. The number means the order in which the switch was added to the cluster. For example, a cluster command switch named eng-cluster could name the fifth cluster member eng-cluster-5. If a switch has a host name, it retains that name when it joins a cluster. It retains that host name even after it leaves the cluster. If a switch received its host name from the cluster command switch, was removed from a cluster, was then added to a new cluster, and kept the same member number (such as 5), the old host name (such as eng-cluster-5) is overwritten with the host name of the cluster command switch in the new cluster (such as mkg-cluster-5). If the switch member number changes in the new cluster (such as 3), the switch retains the previous name (eng-cluster-5). 78-16156-01 Catalyst 3560 Switch Software Configuration Guide 5-13