APPC connections to and from z/OS Communications Server generic resources

If CICS® is a member of a z/OS® Communications Server generic resource group, the local z/OS Communications Server may have an affinity which directs any new binds from a partner to this same local system.

You must not end the affinity held by z/OS Communications Server if there is any possibility that resynchronization with the partner may be needed; if you do, binds (and subsequent resynchronization messages) may be directed to a different member of the generic resource. In most cases, it is safest to allow the APPC connection quiesce protocol to end the affinities automatically—see APPC connection quiesce processing.

CICS prevents the execution of the SET CONNECTION ENDAFFINITY command if a logname has been received from the partner system, because this is the condition under which the partner may begin recoverable work and start resynchronization. The discarding of a connection is also prevented, because its loss means that the logname is no longer visible. If you intend ending affinities, you should do it before shutting down CICS before a cold start, because a cold start restores a logname without the associated connection. Ending affinities without removing the logname can cause exchange logname failures later.

For further information about affinities and how to end them, see Ending affinities.