Publish/subscribe messaging through a link
On a WebSphere MQ link, we can set up publish/subscribe messaging between WebSphere Application Server and the WebSphere MQ publish/subscribe function, or a separate publish/subscribe broker.
The following product versions provide publish/subscribe capability that we can use with WebSphere Application Server over a WebSphere MQ link:
- WebSphere MQ Version 7
- Provides publish/subscribe function that is integrated into WebSphere MQ queue managers. This capability is called integrated publish/subscribe. The publish/subscribe capability for earlier versions of WebSphere MQ is called queued publish/subscribe, because you communicate with a separate publish/subscribe broker by means of messages placed on queues.
- WebSphere Message Broker Version 6
- Provides a separate publish/subscribe broker for queued publish/subscribe. This version of queued publish/subscribe uses MQRFH2 message headers. If we are using WebSphere MQ Version 6, we can use WebSphere Message Broker Version 6 to provide publish/subscribe function that interoperates over a WebSphere MQ link with WebSphere Application Server. From WebSphere Message Broker Version 7, this product no longer provides a separate publish/subscribe broker, and all topic-based publish/subscribe operations made through the product use WebSphere MQ facilities.
- WebSphere Event Broker
- Provides a separate publish/subscribe broker for queued publish/subscribe. This version of queued publish/subscribe is the same as that in WebSphere Message Broker Version 6.
WebSphere MQ Version 6 (except Version 6 of WebSphere MQ for z/OS ) provides queued publish/subscribe that is implemented by a publish/subscribe broker within WebSphere MQ. However, the publish/subscribe function provided by WebSphere MQ Version 6 uses MQRFH message headers, also known as MQRFH1 message headers, and it does not support the MQRFH2 message headers that the WAS publish/subscribe bridge uses on the WebSphere MQ link. For WebSphere MQ Version 6 publish/subscribe to interoperate with WebSphere Application Server publish/subscribe over a WebSphere MQ link, use a separate message broker product that supports MQRFH2 message headers. Alternatively, instead of using a WebSphere MQ link, we can interoperate using the WebSphere MQ messaging provider, so that the applications use WebSphere MQ publish/subscribe function and do not use the service integration bus. This requirement also applies to earlier versions of WebSphere MQ where publish/subscribe function is provided by SupportPac MA0C.
Message headers and contents are mapped in the same way for both point-to-point messages and publish/subscribe messages. For more information about the mapping of messages see How service integration converts messages to and from WebSphere MQ format.
Subtopics
- Publish/subscribe bridge on a WebSphere MQ link
A publish/subscribe bridge enables publish/subscribe messaging between WebSphere Application Server and WebSphere MQ through a WebSphere MQ link. The publish/subscribe bridge provides a connection between the publish/subscribe function of a service integration bus and the publish/subscribe function of a WebSphere MQ network.
- Broker profile on a WebSphere MQ link
A broker profile on a WebSphere MQ link defines a connection through a WebSphere MQ link to a WebSphere MQ queue manager, for the purpose of publish/subscribe messaging with a WebSphere MQ network.
- Topic mapping on a WebSphere MQ link
A topic mapping is an association that defines which messages published in WebSphere Application Server or the WebSphere MQ network, should be forwarded to the other publish/subscribe system.
- Publish/subscribe messaging through a WebSphere MQ link: example
A publish/subscribe bridge over a WebSphere MQ link enables subscribers on the service integration bus in WebSphere Application Server to receive the same published messages as subscribers in a WebSphere MQ network. The broker profile in WebSphere Application Server allows these two separate publish/subscribe domains to appear as a single entity.
Related concepts
Message exchange through a WebSphere MQ link Bus topology that links to WebSphere MQ networks How service integration converts messages to and from WebSphere MQ format
Related information:
Publish/subscribe broker profiles [Settings] Broker profile subscriptions [Collection]