Synchronizing end points after session activation failure

In certain circumstances, VTAM® attempts to recover from an LU failure by automatically issuing a CNOS to resynchronize session limits. If a VTAM negotiates a CNOS request successfully, the negotiated information is saved. If the partner experiences a power failure or other event and terminates all sessions and also loses its session limits, VTAM automatically reissues an internal CNOS request on a subsequent allocation request. (The partner would have to initiate a CNOS request before it could issue an allocation request.) For example, if VTAM cannot activate a session in response to the allocation request, VTAM fails the allocation request, unless it receives one of the following sense codes:

X'08050000'
X'08050001'
X'0835'nnnn, where bytes 2 and 3 contain an offset pointing to a mode name in the user data field and that mode name is not SNASVCMG or CPSVCMG

When VTAM receives any one of these sense codes, VTAM attempts to renegotiate the session limits using an internal CNOS request and issuing the session activation request again. The internal CNOS request uses the values currently in the LU-mode table. These values would have been negotiated successfully on a previous CNOS request.