3.1.6.3 Session Ack Wait Timer Event
The Session Ack Wait Timer event indicates a timeout while waiting for a session acknowledgment from the remote host. When the Session Ack Wait Timer (section 3.1.2.4) expires, the protocol SHOULD apply the following logic to close an idle session:
If there are no packets awaiting acknowledgment, the protocol MUST set the ReceivedAck ADM element to FALSE and MUST NOT restart the Session Ack Wait Timer.
Else if the ReceivedAck ADM element is FALSE, the protocol MUST close the session as specified in section 3.1.5.9.
Else if the ReceivedAck ADM element is TRUE, the protocol MUST restart the Session Ack Wait Timer and set the ReceivedAck ADM element to FALSE.