WebSphere WebSphere Application Server Express, Version 6.0.x Operating Systems: AIX, HP-UX, Linux, Solaris, Windows

Publishing and subscribing with a WebSphere MQ network: example

This topic gives an example of business reasons for creating a publish/subscriber broker profile.

Defining a broker profile is the first step towards enabling subscribers on the service integration bus to receive the same publication messages as subscribers for a message broker in a WebSphere MQ network, that is, IBM WebSphere Business Integration Event Broker or IBM Business Integration Message Broker. This allows these two separate publish and subscribe domains to appear as a single entity.

Imagine that there are two businesses “GolfStats Inc." and “FootballFansData Inc." that each provide a results and news service for different types of sporting event. Both pay third parties to collect sports information (for golf and football respectively) and publish this data to their IT systems. GolfStats and FootballFansData then charge members of the public a monthly fee in exchange for an application that runs on a desktop computer, which pops up the results as they become available.

GolfStats also use their IT system to host a web site and run other business applications, so their IT systems are based on WebSphere Application Server Version 6.0 using the service integration bus, while FootballFansData do not have any other business applications, and use established WebSphere MQ messaging technology and the WebSphere Business Integration Event Broker for their publish/subscribe requirements.

Figure 1. Two separate businesses that publish information to their respective audiences.
The graphic shows (on the left) a  service integration bus in a WebSphere Application Server  owned by 'GolfStats Inc'. In the bus there is a topic space. Coming into the topic space from a publisher outside the bus is the topic 'Sports/golf'. Coming out of the topic space to a subscriber (outside the bus) is the topic 'Sport//.'.  On the right is a  foreign bus in a WebSphere MQ network owned by 'FootballFansData Inc'. In the bus there is a message broker with its queue manager. Coming into the broker's queue manager from a publisher outside the bus is the topic 'Sports/football'. Coming out of the broker's queue manager to a subscriber (outside the bus) is the topic 'Sports/#'. There is no connection between the GolfStats Inc WebSphere Application Server bus and FootballFansData Inc's WebSphere MQ network. The two systems are independent.

The diagram above shows the two separate businesses – GolfStats has a third party who connect to their IT systems when a result becomes available and publish information to a topic space on the topic “sports/golf" which is received by the subscriber(s) subscribing to “sports//." – (//. indicates all sports information). Similarly a third party supplier for FootballFansData publishes information to the WebSphere Business Integration Event Broker on the topic “sports/football" which is received by an Event Broker subscriber application listing all "sports/#" (Event Broker syntax for all sports information).

Recently GolfStats and FootballFansData have merged, and the new management wish to join the existing IT systems together in order to provide information about golf and football to both sets of customers. One option is to migrate all FootballFansData’s IT systems to WebSphere Application Server Version 6.0 using the service integration bus, however this requires significant capital investment as well as upgrading the third party and customer application code to be able to connect to the new systems. A simpler alternative is to bridge between the two systems using the WebSphere Application Server Version 6.0 WebSphere MQ link and a publish/subscribe broker profile.

The actions to achieve this are:

  1. Identify a messaging engine (for example, named LINK_ME) on the GolfStats service integration bus that will act as the link messaging engine to connect to the WebSphere MQ network.
  2. Identify a WebSphere MQ queue manager (for example, named QM_GATEWAY) on the FootballFansData systems that will act as the gateway queue manager to connect to the service integration bus.
  3. Configure a WebSphere MQ link on LINK_ME to enable point-to-point messages to be exchanged between the service integration bus and the WebSphere MQ network.
  4. Define a publish/subscribe broker profile on the WebSphere MQ link that states the name of the message broker in the WebSphere MQ network on which WebSphere Business Integration Event Broker is running: Named QM_ONE in this example.
  5. Define a topic mapping under the publish/subscribe broker profile in order to allow publications to flow between the service integration bus and the WebSphere MQ network. The mapping will be bidirectional on a topic of “sports//." which allows all publications in the sports branch of the topic hierarchy to be transferred.

Once this has been done and the WebSphere Application Server on which the LINK_ME is hosted has been restarted, messages will begin to flow between the two systems. This enables the FootballFansData customers to receive information about golf, and the GolfStats customers to receive information about football. The diagram below shows the logical path of a "golf"message published into the GolfStats IT system being received by a subscriber on the FootballFansData system.

Figure 2. Two separate businesses with one of them publishing to the other.
The graphic shows (on the left) a service integration bus in a WebSphere Application Server  owned by 'GolfStats Inc'. In the bus there is a messaging engine with a broker profile and a WebSphere MQ link (the two are linked). Coming into the broker profile is a connection from a topic space, also on the bus and linked to the broker profile. Coming into the topic space from a publisher outside the bus is the topic 'Sports/golf'.  From the WebSphere MQ link on GolfStats Inc's WebSphere Application Server is a one-way connection flowing to the channels on the foreign bus that represents the WebSphere MQ network. On the right is a  foreign bus in a WebSphere MQ network owned by 'FootballFansData Inc'. In the foreign bus there is a gateway queue manager with WebSphere MQ channels. Connected to the gateway queue manager is 'Queue manager 2'; this queue manager is shown outside the foreign bus. Coming into the broker's queue manager (Queue manager 2) from a subscriber outside the bus is the topic 'Sports/#'.

If GolfStats used the same topic space to publish information on the topic “business/financials" for internal consumption by staff then these messages would not be routed to the WebSphere MQ network of FootballFansData because a topic mapping has not been created for this topic. This ensures that the GolfStats team can limit the people who are able to receive these messages to people authorized to do so on the GolfStats system and avoid unnecessary message traffic between the two systems.


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Last updated: 2 Aug 2005
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