Channels, topics and queues can be created cluster wide, which ensures state is maintained across the cluster as described in the Clustering Overview (see Clusters: An Overview). Once a channel, topic or queue is created as cluster wide, any operations upon that resource are also propagated to all cluster members.

There are a number of ways to create cluster resources once you have created your cluster. The Enterprise Manager application is a tool that provides access to all resources on any realm within a cluster or on standalone realms. This graphical tool is written using the Universal Messaging Client and nAdmin APIs and allows resources to be created, managed and monitored from one central point.

Because the Enterprise Manager tool is written using Universal Messaging's own APIs, all operations you can perform using the tool are also available programmatically using the Universal Messaging APIs, allowing you to write customized applications for specific areas of interest within a realm or a cluster.

Once a realm is part of a cluster, you can centrally manage its resources and configuration. For example, realm access control lists (ACLs) can be updated on any member realm and the change will be propagated to all other member realms. Clustered channels and queue ACLs can also be changed on any cluster member and the change is then propagated to the other cluster members. Configuration changes (in the Enterprise Manager tool) can also be made on one realm and propagated to all other realms in the cluster.

This provides a powerful way of administering your entire Universal Messaging environment and its resources.