3.1.5.5 Receiving a SessionAck Packet

If the SessionState ADM element is not set to the value OPEN, the protocol MUST close the session as specified in Closing a Session (section 3.1.5.9).

A SessionHeader ([MS-MQMQ] section 2.2.20.4) contains a session acknowledgment that acknowledges express and recoverable messages. A SessionHeader can appear in a SessionAck Packet or can be piggy-backed onto a UserMessage Packet ([MS-MQMQ] section 2.2.20). A SessionHeader is present in the packet when the Flags.SH bit field of the BaseHeader ([MS-MQMQ] section 2.2.19.1) is set.

The protocol MUST perform the following steps to process a SessionHeader: