# Protocol stack (TCP)

Mumble has a shallow and easy to understand stack. Basically it
uses Google's Protocol Buffers[^1] with simple prefixing to
distinguish the different kinds of packets sent through a TLSv1
encrypted connection. This makes the protocol very easily expandable.

![resources/mumble_packet.png](Mumble packet)

The prefix consists out of the two bytes defining the type of the packet
in the payload and 4 bytes stating the length of the payload in bytes
followed by the payload itself. The following packet types are available
in the current protocol and all but `UDPTunnel` are simple protobuf messages.
If not mentioned otherwise all fields outside the protobuf encoding are *big-endian*.

| Type | Payload             |
| ---- | ------------------- |
| `0`  | Version             |
| `1`  | UDPTunnel           |
| `2`  | Authenticate        |
| `3`  | Ping                |
| `4`  | Reject              |
| `5`  | ServerSync          |
| `6`  | ChannelRemove       |
| `7`  | ChannelState        |
| `8`  | UserRemove          |
| `9`  | UserState           |
| `10` | BanList             |
| `11` | TextMessage         |
| `12` | PermissionDenied    |
| `13` | ACL                 |
| `14` | QueryUsers          |
| `15` | CryptSetup          |
| `16` | ContextActionModify |
| `17` | ContextAction       |
| `18` | UserList            |
| `19` | VoiceTarget         |
| `20` | PermissionQuery     |
| `21` | CodecVersion        |
| `22` | UserStats           |
| `23` | RequestBlob         |
| `24` | ServerConfig        |
| `25` | SuggestConfig       |

For raw representation of each packet type see the [`Mumble.proto`](https://github.com/mumble-voip/mumble/blob/master/src/Mumble.proto)
and [`MumbleUDP.proto`](https://github.com/mumble-voip/mumble/blob/master/src/MumbleUDP.proto) files.

[^1]: <https://github.com/google/protobuf>