This section describes the terminology of intra-group queuing.
Intra-group queuing can effect potentially fast and less expensive message transfer between queue managers in a queue-sharing group, without the need to define channels.
Each queue-sharing group has a shared transmission queue called SYSTEM.QSG.TRANSMIT.QUEUE for use by intra-group queuing. If intra-group queuing is enabled, SYSTEM.QSG.TRANSMIT.QUEUE appears in the name resolution path when opening remote queues. When applications (including Message Channel Agents (MCAs)) put messages to a remote queue, the local queue manager determines the eligibility of messages for fast transfer and places them on SYSTEM.QSG.TRANSMIT.QUEUE.
The IGQ agent is the task, started at queue manager initialization, that waits for suitable messages to arrive on the SYSTEM.QSG.TRANSMIT.QUEUE. The IGQ agent retrieves suitable messages from this queue and delivers them to the destination queue(s).
The IGQ agent for each queue manager is always started because intra-group queuing is used by the queue manager itself for its own internal processing.