How WebSphere MQ link handles reply-to topics

This text describes how reply-to topics, a feature of WebSphere® MQ, are handled by WebSphere MQ link.

A WebSphere Application Server JMS application can publish a message to a topic space with a reply-to topic which is received by the publish/subscribe bridge on the WebSphere MQ link and passed to a message broker in a WebSphere MQ network. The WebSphere MQ JMS application receives the message from the message broker, obtains the reply destination and publishes a message to the message broker on the reply topic. In order for the reply message to be routed back to WebSphere Application Server subscribers, the administrator must have configured a topic mapping from WebSphere MQ to WebSphere Application Server on the reply topic (unless it is a temporary reply topic, as described below.)

A WebSphere MQ JMS application can publish a message to a broker with a reply-to topic which is received by the WebSphere Application Server application. An example is a WebSphere MQ JMS application publishing to a message broker in the WebSphere MQ network, on "myTopic" with a reply topic of "myReplyTopic". A mapping must have already been specified on the publish/subscribe bridge so that the publish/subscribe bridge is subscribing to "myTopic" on the message broker. When the message is sent over the WebSphere MQ link it is translated into the correct format, and delivered to the publish/subscribe bridge subscriber queue where it is processed and then sent on to the topic space as specified in the publish/subscribe topic mapping. It is then received by the WebSphere Application Server JMS application, which sends a reply message back to the message broker on the WebSphere MQ network by way of the publish/subscribe bridge. You must already have created a mapping to forward messages published on "myReplyTopic" from WebSphere Application Server to the WebSphere MQ broker.

The exceptions to this rule are temporary topic reply destinations which are automatically routed back across the WebSphere MQ link by the publish/subscribe bridge, without any intervention from the administrator. See Request-reply across the WebSphere MQ link for more information.
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.




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Last updatedLast updated: Aug 30, 2013 8:21:57 PM CDT
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