There are many ways to make digital Audio connections. Some are point to point (Layer2), some are real network protocol versions (Layer3). Hereunder is a summation of the existing protocols: Audio Network Types
Here are the readers of the courses by Jan Panis for AOS. Basic Electronics for MT1, Network theory and Network audio for MT2, basics of Sounddesign with loudspeakers and the basics of Vectorworks CAD drawing for TTS2. or TTS2. Look in the specific chapters!