You can connect buses in different ways depending on your requirements.
For example, you can link messaging engines to distribute message workload,
and to provide system availability in the event of system failure.
A topology that consists of just one messaging engine may be adequate for
some applications. Deploying more than one messaging engine, and linking them
together, has advantages:
- Distributes the messaging workload across multiple servers.
- Positions message processing close to the applications that are using
it, and reduces network traffic. For example, if both sending and receiving
applications are running in the same server process, it is inefficient to
route all the messages that flow between the two applications through a messaging
engine running in a remote server.
- Improves availability in the event of system or link failure. For example,
your bus topology can remove a single point of failure, and allow store and
forward between two servers.
- Provides improved scalability.
- Accommodates firewalls, or other network restrictions that limit the ability
of network hosts to connect to a single messaging engine.
A bus topology can contain links to WebSphere MQ networks. This allows
messages to flow between applications connected to a WebSphere MQ queue manager
and applications attached to a service integration bus.