Explicit and undetermined connection termination

Ideally, a UA will gracefully close its TCP connection to the Oracle Communications Unified Session Manager, and in turn the socket pair will be considered closed with the UA being unreachable. In less ideal cases, the UA goes dark and no response is received when expected. The Oracle Communications Unified Session Manager considers the unresponsive UA as unreachable as call attempts time out. Provisions then begin to remove that contact from the registration cache and then the ENUM user database.