News release confirmed that, just as when a response message QOS.
QOS: Quality of Service Quality of Service, is an effort to provide a differential for different types of traffic flows (that is "different") Class of Service technology. Can provide more priority to those service levels for sensitive traffic stream bandwidth, delay, jitter, packet loss rate by QoS, enables business users to meet normal demand for high-performance use.
3.4 PUBACK - release confirmed
PUBACK packet is a response to a QoS level PUBLISH data packet.
3.4.1 Fixed Header fixed title
FIG 3.12 - PUBACK fixed packet header
| Place |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Byte 1 |
MQTT control packet type (4) |
reserved |
||||||
|
|
0 |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
| Byte 2 |
The remaining length (2) |
|||||||
|
|
0 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
The remaining length field
This is a variable length header. For PUBACK packet, a value of 2.
3.4.2 Variable Header variable head
It contains the identifier of the data packet being acknowledged PUBLISH packet.
FIG 3.13 - PUBACK packet header variables
| Place |
7 |
6 |
Fives |
4 |
3 |
2 |
1 |
0 |
| Byte 1 |
MSB packet identifier |
|||||||
| Byte 2 |
LSB packet identifier |
|||||||
3.4.3 Payload Payload
PUBACK packet no load.
3.4.4 Actions Action
This is described in detail in Section 4.3.2.