ResvTear Messages
ResvTear messages remove reservation states along a path. These messages travel upstream toward senders of the session. In a sense, ResvTear messages are the reverse of Resv messages. ResvTear messages typically are initiated by a receiver application or by a router when its reservation state times out.
ResvTear messages are not required, but they enhance network performance because they release network resources quickly. If ResvTear messages are lost or not generated, reservation states eventually time out when they are not refreshed, and the resources associated with the reservation are released.