16.10 Considerations When Using Clustering over the WAN

This topic describes what needs to be considered when you use clustering over the WAN.

  • Basic configuration mode:
    1. All Cisco Unified Communications Manager servers use the same primary or secondary SAF forwarders.
  • Advanced configuration mode:
    1. Multiple sets of forwarders can be configured and individually applied to Cisco Unified Communications Manager servers.
    2. This mode is required when clustering over the WAN is used.

When you configure a Cisco Unified Communications Manager cluster with one or more SAF forwarders, by default, all Cisco Unified Communications Manager nodes that are applied to the SAF-enabled trunk or trunks via the device pool will register with the configured SAF forwarder.

First, you must make sure that each local node uses a different SAF client ID. You can easily check the nodes by using a SAF client name that ends with @. In this case, each node will utilize the configured name that is followed by @ and a unique node ID. At the SAF forwarder, you must add the basename keyword to the end of the SAF external-client client-ID command, or you must manually configure all names that are used by the nodes in your cluster.

In some cases, you may not want all nodes that should use SAF to register with all configured SAF forwarders. For example, as shown in the figure, when you use clustering over the WAN, you typically want to register nodes with their local SAF forwarders only. For that configuration, click the Show Advanced link at the SAF forwarder configuration page.

At the advanced configuration mode page, you can associate individual members of the cluster selectively with the configured SAF forwarders.