Multiple Systems Coupling in an IMSplex

The Multiple Systems Coupling (MSC) function allows you to distribute and balance your workload across multiple systems.

MSC distributes transaction and message traffic between IMS subsystems. MSC extends its communication with IMS and scheduling capabilities, enabling you to perceive one virtual IMS system, when in fact transactions are being routed among several IMS subsystems.

An MSC network can coexist with an IMSplex using shared queues. A temporary MSC and IMSplex coexistence can be useful if you are migrating from an MSC network to an IMSplex configuration. Coexistence can also be permanent, such as when an MSC link connects an IMSplex to an IMS system outside of the IMSplex.

In both coexistence examples, you must consider the proper routing and processing of your transaction messages across both the MSC and IMSplex environments, because each environment uses a different routing method. Generally, MSC networks route transactions to specific IMS systems using SYSIDs. IMSplex systems with shared queues route transactions by making them available on the shared queue to any IMS system that registers an interest in the transactions. When an MSC network and an IMSplex with shared queues coexist, both of these methods of routing can apply to transactions.

For more information on the coexistence of MSC systems and IMSplex systems, see IMS Version 15.4 Communications and Connections.