This topic describes the types of request-reply messages that can
be exchanged across the WebSphere MQ link.
Request-reply exchanges can be:
- Point-to-point messages.
- Queue type reply-to destination.
- Topic type reply-to destination.
- Publication messages.
- Queue type reply-to destination.
- Topic type reply-to destination.
Queue type reply messages (replies sent to a queue-type destination) cross
the WebSphere MQ link automatically in the same way as point-to-point request
messages.
Topic type replies cross the WebSphere MQ link through the publish/subscribe
bridge and are of two varieties:
- Permanent reply-to topics. For a reply message published to a permanent
topic to cross between a WebSphere Application Server and a WebSphere MQ network,
the administrator must first define an appropriate topic mapping (defining
the topic name and direction) on the publish/subscribe bridge associated with
the WebSphere MQ link.
- Temporary topic replies. A temporary topic reply message is automatically
routed between a WebSphere Application Server and a WebSphere MQ network by
the publish/subscribe bridge. This is because the temporary topic name is
assigned at runtime and so a topic mapping cannot be defined. The exception
to this is that only temporary topic replies to publication messages are supported
(that is, point-to-point request messages with temporary topic reply destinations
are not supported).
Note: for temporary topic reply messages to be routed from
the service integration bus back to WebSphere MQ through the publish/subscribe
bridge, you must configure the broker stream queue of the mapping on which
the request message is sent. This field will already be specified for bi-directional
topic mappings. While it is not a mandatory field for "From MQ" topic mappings,
it must be completed if you want temporary topic reply messages to be routed.