Cross-system coupling (XCF) services allow multiple instances of an application or subsystem, running on different systems in a sysplex, to share status information and communicate with each other.

Your application or subsystem might consist of multiple instances, each running on a different system in the same sysplex. Typically, each instance performs certain functions for the application as a whole. For example, one instance of a database application might write changed database information to permanent storage on behalf of all instances of the application. Alternatively, each instance could perform all the application's functions on a given system.