PUBCOMP Assured publish complete (part 3)

This message is either the response from the broker to a PUBREL message from a publisher, or the response from a subscriber to a PUBREL message from the broker. It is the fourth and last message in the QoS 2 protocol flow.

Fixed header

The table below shows the fixed header format.

bit 7 6 5 4 3 2 1 0
byte 1 Message Type (7) DUP flag QoS level RETAIN
  0 1 1 1 x x x x
byte 2 Remaining Length (2)
  0 0 0 0 0 0 1 0
QoS level
Not used.
DUP flag
Not used.
RETAIN flag
Not used.
Remaining Length field
The length of the variable header (2 bytes). It can be a multibyte field.

Variable header

The variable header contains the same Message ID as the acknowledged PUBREL message.

bit 7 6 5 4 3 2 1 0
byte 1 Message ID MSB
byte 2 Message ID LSB

Payload

There is no payload.

Actions

When the client receives a PUBCOMP message, it discards the original message because it has been delivered, exactly once, to the broker.

Related concepts
WebSphere MQ Telemetry Transport

Related reference
PUBREL Assured Publish Release (part 2)
WebSphere MQ Telemetry Transport fixed header
WebSphere MQ Telemetry Transport variable header
WebSphere MQ Telemetry Transport Quality of Service levels and flows