WebSphere Message Brokers
File: ac10980_
Writer: Kate Hostler

Reference topic

This build: July 31, 2007 21:18:09

PUBREC Assured publish received (part 1)

A PUBREC message is the response to a PUBLISH message with QoS level 2. It is the second message of the QoS level 2 protocol flow. A PUBREC message is sent by the broker in response to a PUBLISH message from a publishing client, or by a subscriber in response to a PUBLISH message from the broker.

Fixed header

The table below shows the fixed header format.

bit 7 6 5 4 3 2 1 0
byte 1 Message Type (5) DUP flag QoS level RETAIN
  0 1 0 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 Message ID for the acknowledged PUBLISH. The table below shows the format of the variable header.

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 it receives a PUBREC message, the recipient sends a PUBREL message to the sender with the same Message ID as the PUBREC message.

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Copyright IBM Corporation 1999, 2007Copyright IBM Corporation 1999, 2007. All Rights Reserved.
This build: July 31, 2007 21:18:09

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