This topic describes what is referred to as the publish/subscribe
bridge, which consists of broker profiles and topic mappings on the WebSphere® MQ link.
Defining a publish/subscribe bridge, that is, broker profiles and
topics mappings, allows publication and subscription between WebSphere Application Server and a broker
in a WebSphere MQ network
making a WebSphere Application Server and WebSphere MQ look like part
of the same system. Publications can flow to and from the WebSphere Business Integration
brokers, even simultaneously in both directions on the same topic.
- Multiple broker profiles can be defined. See Broker profile. Publications flow between
the two sides of the publish/subscribe bridge according to the topic
mappings that are defined. See Topic mapping.
- The bridge itself connects as a regular subscriber and publisher
to message brokers in a WebSphere MQ
network. For example, for publications to move between WebSphere Application Server and WebSphere MQ, the publish/subscribe
bridge attaches as a durable subscriber to the relevant topic space
and so receives messages when they are published on that topic. The
publish/subscribe bridge then attaches as a publisher to, say IBM® WebSphere Business Integration Event Broker,
and republishes the message into the WebSphere MQ network where it can be received
by Event Broker subscribers.
- If communication between the two sides of the publish/subscribe
bridge fails messages are held on each side until communication is
reestablished by the system or by the administrator. If a WebSphere Business Integration
message broker fails it will publish no new messages. You may wish
to contact the broker administrator to ask for the failure to be resolved
and for the publication flow to resume. Messages published by WebSphere Application Server applications
are transferred to WebSphere MQ
and build up on broker input queues until the broker resumes processing.
If WebSphere MQ fails,
the message broker is unable to publish messages. Messages published
by WebSphere Application Server applications
cannot be transferred to WebSphere MQ
so they build up on the transmission queue, waiting for server channel
communications to be resumed.