Topic root (TPROOT)

This attribute specifies the topic root for an AMQP channel.

We can use the TPROOT attribute to specify a topic root for an AMQP channel. Using this attribute ensures that an MQ Light application, when deployed to a queue manager, does not publish or subscribe to messages to or from areas of the topic tree that are being used by other applications.

The default value for TPROOT is SYSTEM.BASE.TOPIC. With this value, the topic string an AMQP client uses to publish or subscribe has no prefix, and the client can exchange messages with other MQ pub/sub applications. To have AMQP clients publish and subscribe under a topic prefix, first create an MQ topic object with a topic string set to the prefix we want, then change the value of the AMQP channel TPROOT attribute to the name of the MQ topic object you created. The following example shows the topic root being set to APPGROUP1.BASE.TOPIC for AMQP channel MYAMQP:

DEFINE CHANNEL(MYAMQP) CHLTYPE(AMQP) TPROOT(APPGROUP1.BASE.TOPIC) PORT(5673)

Note: If the TPROOT attribute value, or the topic string that underpins it, is changed, existing AMQP topics and their messages might be orphaned. Parent topic: Channel attributes in alphabetical order