Apart from the exception conditions identified in 5.3.2 and 5.8, the network shall initiate clearing by sending a DISCONNECT message, and entering the Disconnect Indication state. The DISCONNECT message is a local invitation to clear and does not imply that the B-channel has been disconnected at the user-network interface.
Note - When the network initiates clearing by sending a RELEASE message, the procedures described in 5.3.3 are followed.