| Value | Meaning |
|---|---|
| RESERVED10 | Forbidden - Reserved |
| CONNECT1 | Client -> Server - Client request to connect to Server |
| CONNACK2 | Server -> Client - Connect acknowledgment |
| PUBLISH3 | Publish message |
| PUBACK4 | Publish acknowledgment |
| PUBREC5 | Publish received (assured delivery part 1) |
| PUBREL6 | Publish release (assured delivery part 2) |
| PUBCOMP7 | Publish complete (assured delivery part 3) |
| SUBSCRIBE8 | Client -> Server - Client subscribe request |
| SUBACK9 | Server -> Client - Subscribe acknowledgment |
| UNSUBSCRIBE10 | Client -> Server - Unsubscribe request |
| UNSUBACK11 | Server -> Client - Unsubscribe acknowledgment |
| PINGREQ12 | Client -> Server - PING request |
| PINGRESP13 | Server -> Client - PING response |
| DISCONNECT14 | Client -> Server - Client is disconnecting |
| RESERVED215 | Forbidden - Reserved |
MQTT Control Packet type
http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Table_2.1_-