When the publishing load increases, you scale up client-side message distribution by creating a cluster of Brokers to handle the increasing load. Clusters enable scalability and availability of your messaging system. A cluster is similar to a territory, except that document forwarding within a cluster is disabled. The JMS subscriber is connected to all the Brokers in a cluster, and receives the documents published to any of the Brokers in the cluster.

Clusters facilitate client-side load balancing and failover when you use JMS cluster policies for client connections. For more information, see the webMethods Broker Messaging Programmer’s Guide.

For additional flexibility, you can create multiple clusters and link them together using cluster gateways. A cluster gateway is a connection that allows specified documents to flow between two clusters. For more information about cluster gateways, see Managing Cluster Gateways.