SYSTEM.BASE.TOPIC

Base topic for ASPARENT resolution. If a particular topic has no parent administrative topic objects, or those parent objects also have ASPARENT, any remaining ASPARENT attributes are inherited from this object.

Table 1. Default values of SYSTEM.BASE.TOPIC

Parameter	Value
TOPICSTR	"
CLROUTE	DIRECT
CLUSTER	The default value is an empty string.
COMMINFO	SYSTEM.DEFAULT.COMMINFO.MULTICAST
DEFPRESP	SYNC
DEFPRTY	0
DEFPSIST	NO
DESCR	'Base topic for resolving attributes'
DURSUB	YES
MCAST	DISABLED
MDURMDL	SYSTEM.DURABLE.MODEL.QUEUE
MNDURMDL	SYSTEM.NDURABLE.MODEL.QUEUE
NPMSGDLV	ALLAVAIL
PMSGDLV	ALLDUR
PROXYSUB	FIRSTUSE
PUB	ENABLED
PUBSCOPE	ALL
QSGDISP ( z/OS® platform only)	QMGR
SUB	ENABLED
SUBSCOPE	ALL
USEDLQ	YES
WILDCARD	PASSTHRU

If this object does not exist, its default values are still used by IBM MQ for ASPARENT attributes that are not resolved by parent topics further up the topic tree.

Setting the PUB or SUB attributes of SYSTEM.BASE.TOPIC to DISABLED prevents applications publishing or subscribing to topics in the topic tree, with two exceptions:

1. Any topic objects in the topic tree that have PUB or SUB explicitly set to ENABLE. Applications can publish or subscribe to those topics, and their children.
2. Publication and subscription to SYSTEM.BROKER.ADMIN.STREAM is not disabled by the setting the PUB or SUB attributes of SYSTEM.BASE.TOPIC to DISABLED.

See also Special handling for the PUB parameter.