We recommend a global bandwidth of 100kb/s for transmission and 100kb/s for reception on the user side.
100kb are ideal for HD voice calls via Chrome with tunneling: at 48kb/s in bitrate + 20kb/s of error correction + TURN/TLS headers with an upper limit of 100kb/s.
For a classic SIP call via IP phone:
Codec G711: 64kb/s
Codec Opus: 12.4kb/s => 48kb/s +/- error correction