- Is a separate app that handles UDP voice packets from the game (basically just sends them unchanged to other active members of the voice channel)
- Is the one made by Ascent Team (specifically, by Burlex) back in 2007-08, just with couple opcodes added and CmakeLists.txt https://github.com/SkyFire/ascent_classic/tree/master/src/ascent-voicechat
- Can be on a separate host, but requires a TCP connection to world server and a UDP connection for users to connect. Ports are configurable
- Builds on Windows and Linux, but I think it doesn't support -c parameter for config file so probably uses current directory when you start it
World server should handle opcodes, request & manage voice channels while being connected to Voice Chat server, so core change is needed
- CMaNGOS PR: cmangos/mangos-tbc#668
