MQI client: Client Channel Definition Table (CCDT)

You can connect an IBM® MQ MQI client application to any level of queue manager. If the client uses a CCDT, it must use a CCDT built by the same or earlier version of queue manager. If the client connects without using a CCDT, this restriction does not apply.

In a common migration scenario, if you upgrade a Version 6.0 queue manager to Version 7.5, and you do not create new CCDTs for its clients, the clients connect to the Version 7.5 queue manager without any changes being required. Client behavior might change as a result of changes to the queue manager.

Another common migration scenario is to update some queue managers and some clients to Version 7.5, leaving some queue managers and clients at Version 6.0. In this scenario, you want to update the CCDT for Version 7.5 IBM MQ MQI client connected to Version 7.5 queue managers to Version 7.5, so that the clients can exploit Version 7.5 function fully. The new clients also connect to Version 6.0 queue managers. Existing clients connect to both Version 6.0 and Version 7.5 queue managers. In order that Version 7.5 clients can exploit new Version 7.5 function, you must deploy a Version 7.5 CCDT to Version 7.5 clients. Version 6.0 clients must continue to use the Version 6.0 CCDT. Both sets of clients can connect to both sets of queue managers, regardless of the CCDT they are using.

If the client is an IBM MQ MQI client, the version of the IBM MQ MQI client libraries linked to by the client must be the same or greater than the version of the queue manager that was used to build the CCDT. If the client is a Java or JMS client, then the client must be built with versions of the IBM MQ JAR files that are the same or greater than the queue manager that was used to build the CCDT.

To upgrade a Version 6.0 IBM MQ MQI client to use a Version 7.5 CCDT, you must upgrade the IBM MQ MQI client installation to Version 7.5. Unless you decide to do so for other reasons, do not rebuild the client application.

To upgrade a Version 6.0 Java or JMS client to use a Version 7.5 CCDT, redeploy the IBM MQ JAR files to the client workstation. You do not need to rebuild the Java or JMS client with the new JAR files.