WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

10.4.2 Choosing a messaging topology
The following topologies are some of the ones implemented by the WebSphere
Application Server default messaging provider (in increasing complexity) using
the previously defined concepts.
One bus, one bus member (single server)
This is the simplest and most common topology. It is used when applications
deployed to the same application server need to communicate among
themselves. Additional application servers that are not members of the bus and
only need to use bus resources infrequently can connect remotely to the
messaging engine. See Figure 10-2.
Local
connection
Application server
Messaging
application
MDB
Messaging
application
Messaging
Engine
Queue point
Messages
Queue destination
Figure 10-2 Single bus with an application server member
Although this is simple to set up, there might be a performance impact for
message producers and consumers that connect to the messaging engine
remotely. Because the single messaging engine is running on a non-clustered
application server, no high availability or workload management is supported.
One bus, one bus member (a cluster)
With this variation, the bus member is a cluster. By default, only one application
server in a cluster has an active messaging engine on a bus. If the server fails,
the messaging engine on another server in the cluster is activated. This provides
failover, but no workload management.
344 WebSphere Application Server V7.0: Concepts, Planning, and Design
Application server
Bus
Messaging
application
Remote
connection