Chapter 10. Broker Federation

Broker Federation allows messaging networks to be defined by creating message routes, in which messages in one broker (the source broker) are automatically routed to another broker (the destination broker). These routes can be defined between exchanges in the two brokers (the source exchange and the destination exchange), or from a queue in the source broker (the source queue) to an exchange in the destination broker.

Message routes are unidirectional; when bidirectional flow is needed, one route is created in each direction. Routes can be durable or transient. A durable route survives broker restarts, restoring a route as soon as both the source broker and the destination are available. If the connection to a destination is lost, messages associated with a durable route continue to accumulate on the source, so they can be retrieved when the connection is reestablished.

Broker Federation can be used to build large messaging networks, with many brokers, one route at a time. If network connectivity permits, an entire distributed messaging network can be configured from a single location. The rules used for routing can be changed dynamically as servers or responsibilities change at different times of day, or to reflect other changing conditions.