Publish/subscribe messaging through an IBM link
The following products provide publish/subscribe capability we can use with WAS over an IBM MQ link:
- IBM MQ v7 and later
- Provides a publish/subscribe function integrated into IBM MQ queue managers. This capability is called integrated publish/subscribe. The publish/subscribe capability for earlier versions of IBM 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
- Provides a separate publish/subscribe broker for queued publish/subscribe. This version uses MQRFH2 message headers. If we are using IBM MQ Version 6, we can use WebSphere Message Broker Version 6 to provide publish/subscribe function that interoperates over an IBM MQ link with WAS. From WebSphere Message Broker v7, this product no longer provides a separate publish/subscribe broker, and all topic-based publish/subscribe operations made through the product use IBM MQ facilities.
Note that WebSphere Message Broker is no longer supported. Use either IBM App Connect Enterprise (IBM ACE) or IBM Integration Bus.
- 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 v6.
IBM MQ v6 (except v6 of IBM MQ for z/OS ) provides queued publish/subscribe implemented by a publish/subscribe broker within IBM MQ. However, the publish/subscribe function provided by IBM 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 IBM MQ link. For IBM MQ v6 publish/subscribe to interoperate with WAS publish/subscribe over an IBM MQ link, we must use a separate message broker product that supports MQRFH2 message headers. Alternatively, instead of using an IBM MQ link, we can interoperate using the IBM MQ messaging provider, so that the applications use IBM MQ publish/subscribe function and do not use the service integration bus. This requirement also applies to earlier versions of IBM 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 IBM MQ format.
Subtopics
- Publish/subscribe bridge on an IBM MQ link
- Broker profile on an IBM MQ link
- Topic mapping on an IBM MQ link
- Publish/subscribe messaging through IBM MQ link: example
Related:
Message exchange through an IBM MQ link Bus topology that links to IBM MQ networks How service integration converts messages to and from IBM MQ format Publish/subscribe broker profiles [Settings] Broker profile subscriptions [Collection]