Following the receipt of a SUSPEND message, the network enters the Suspend Request state. After a positive validation of the received call identity, the network shall send a SUSPEND ACKNOWLEDGE message, and start timer T307. (The value of T307 is specified in 9.1.)
At this time, the network shall consider the call reference to be released and enter the Null state for that call reference. The call identity associated with the suspended call has to be stored by the network and cannot be accepted for another suspension until it is released.
The B-channel involved in the connection will be reserved by the network until reconnection of the call (or until a clearing cause occurs, e.g. expiry of timer T307). A NOTIFY message with notification indicator No. 0 (user suspended) is sent to the other user.
When the user receives the SUSPENDACKNOWLEDGE message, the user shall stop timer T319, release the B-channel and call reference, and enter the Null state.
Following the receipt of the SUSPENDACKNOWLEDGE message, the user may disconnect the underlying data link connection. In any case, if the user physically disconnects from the interface without having disconnected the data link connection, standard data link layer procedures are started by the network side of the data link layer supervision,resulting in the release of the data link layer connection.