292 WebSphere Application Server V8.5 Concepts, Planning, and Design Guide
Service integration bus
A service integration bus and a message engine are key components in an infrastructure.
WebSphere Application Server offers the ability to scale messaging resources. You can use
the scalability policy provided by WebSphere: One service integration bus is hosted by a
WebSphere Application Server cluster. You can choose a horizontal cluster, a vertical cluster,
or both. Each cluster member has one message engine. All the message engines are active
at the same time, and each message engine can run only on its own JVM. If the JVM fails, the
message engine is unavailable.
WebSphere Application Server manages the workload between the message engines. ...