From Quake Wiki
A Network Protocol defines how the Quake client and server communicate after the initial connection is established. Originally Quake only had one protocol, now called the Netquake Protocol. Later id Software released QuakeWorld, which included a major overhaul of the protocol designed to work well over higher-latency internet connections. Now that the source code is released, several custom engines have introduced their own network protocols to extend limits or add capabilities. When a client connects to a server, the server informs the client which protocol is being used, and the client will either adapt its behavior or disconnect if it does not recognize the protocol or cannot support it.
List of Protocols
TODO: this list should be edited for accuracy, this was cobbled together from snippets of info -metlslime
|15||Netquake Protocol|| quake.exe
|Orignal Quake protocol|
|15||QUAKEDP||LH: "darkplaces extended quake protocol (used by TomazQuake and others), backwards compatible as long as no extended features are used"|
|15||TOMAZ||LH: "this unfortunately does not match up with the QUAKEDP protocol it claims to use, it has some different entity encodings, and it's not easy to fix this"|
|15||NEH15||almost same as 15, 8-12 byte transparency/fullbright data added on to entities. used by joequake, nehahra, and bjp (with sv_protocol 15)|
|28||Quakeworld Protocol|| qwcl.exe
|id Software's improved protocol, optimized for netplay.|
|28||FTEQW||LH: "I do not know the details of this, but it uses the same QW protocol ID, it negotiates extra features on connect, I don't know how well demo playback works."|
|96||DARKPLACES1||LH: "uses EntityFrame entity snapshot encoder/decoder which is a QuakeWorld-like entity snapshot delta compression method"|
|97||DARKPLACES2||LH: "various changes"|
|250||NEHAHRAMOVIE||LH: "Nehahra movie protocol, a big nasty hack dating back to early days of the Quake Standards Group (but only ever used by neh_gl.exe), this is potentially backwards compatible with quake protocol as long as no extended features are used (but in actuality the neh_gl.exe which wrote this protocol ALWAYS wrote the extended"|
|666||Fitzquake Protocol|| Fitzquake
|Fitzquake protocol, introduced in version 0.85, supports more models, sounds, frames, edicts, adds entity alpha, high-precision client aim, and a few other things.|
|3500||DARKPLACES3||LH: "uses EntityFrame4 entity snapshot encoder/decoder which is broken, this attempted to do partial snapshot updates on a QuakeWorld-like protocol, but it is broken and impossible to fix"|
|3501||DARKPLACES4||LH: "various changes"|
|3502||DARKPLACES5||LH: "uses EntityFrame5 entity snapshot encoder/decoder which is based on a Tribes networking article at "|
|3503||DARKPLACES6||LH: "various changes"|
|3504||DARKPLACES7||LH: "added QuakeWorld-style movement protocol to allow more consistent prediction"|
| LH: "same as NEH15 but with 16bit modelindex"|
BJP: "Extended protocol (models > 256 etc), hopefully no conflict"
| LH: "same as NEHAHRABJP but with 16bit soundindex"|
BJP: "Extended protocol (sounds > 256), problems with Marcher (Some progs (Marcher) send sound services)"
| LH: "same as NEHAHRABJP2 but with some changes"|
BJP: "Extended protocol (sounds > 256), more compatible, but less functional"
|10003||MH||DirectQ||MH: "Extended protocol, as 10002 but extends coords to full float"|