Message routing across MSC and IMSplex environments

MSC uses local and remote SYSIDs and destination names to route messages across links between local, intermediate, and remote IMS systems in an MSC network. IMSplexes with shared queues use destination name registration, IMSIDs, a shared queue, and the registered interest of IMS systems to route messages between front-end and back-end IMS systems in an IMSplex. When an IMSplex and an MSC network coexist, both methods of routing can be used.

In MSC networks and IMSplexes with shared queues, IMS stores the SYSID, destination name, and IMSID value in the message prefix when IMS builds the message and places it on a local or shared queue. The SYSID, destination name, or IMSID stored in the message prefix must match the SYSID, destination name, or IMSID of an IMS system in either the IMSplex or the MSC network. If they do not match, any messages on the shared queue or in flight in the MSC network will trigger a routing error, such as a pseudoabend U0830, when an IMS system attempts to process the message. This condition can occur, for example, if the IMS system that owns the SYSID, destination name, or IMSID is down or has changed its value.