DISCONNECT Disconnect notification

The DISCONNECT message is sent from the client to the broker to indicate that it is about to close its TCP/IP connection. This allows for a clean disconnection, rather than just dropping the line.

Sending the DISCONNECT message does not affect existing subscriptions. They are persistent until they either explicitly unsubscribed, or if there is a clean start. The broker retains QoS 1 and QoS 1 messages for topics to which the client is unsubscribed until the client reconnects. QoS 0 messages are not retained, since they are delivered on a best efforts basis.

Fixed header

The fixed header format is shown in the table below.

bit 7 6 5 4 3 2 1 0
byte 1 Message Type (14) DUP flag QoS level RETAIN
  1 1 1 0 x x x x
byte 2 Remaining Length (0)
  0 0 0 0 0 0 0 0

The DUP, QoS, and RETAIN flags are not used in the DISCONNECT message.

Payload

There is no payload.

Variable header

There is no variable header.