A message was received in the Session Layer that implies a violation of the Session Layer protocol. This may be any verb received out-of-sequence on an established connection, or any verb other than an S-Connect received when the identified session does not exist. This will only occur if the peer entity does not implement its Session protocols correctly, or during the short period while a session is being torn down abruptly. If all Sessions/Associations are terminated with the graceful Release protocols, this will never occur. When one side of a communication dies, it is possible that one or more messages will flow from the upper layers of CMIP services before this is noticed. This will cause the messages that cause this error to be logged to be lost, just as they will be after the upper layers are notified, because the session/association they need to use is no longer in existence.