Immediate deactivation is specified with the TYPE=IMMED operand of the VARY INACT command. When immediate deactivation is requested, LU-LU sessions associated with the resources are effectively broken. All queued requests for sessions involving the resources to be deactivated are discarded, and the initiators are notified. No new requests for sessions involving these resources are accepted. All input and output operations for active LU-LU sessions are immediately halted, with possible loss of data. If the deactivated logical unit is in session with an application program, the application program is notified of the deactivation. The application program must complete the session termination for the deactivation to be completed.

Immediate deactivation provides tight control over the domain; normal deactivation provides less stringent control, but allows for a more orderly deactivation. Normal and immediate deactivations are not completed until the proper SNA requests and responses are exchanged between the VTAM® SSCP and the affected resources. If conditions in the domain prevent the sending of the proper requests or responses, normal and immediate deactivation might not be successful.