For backwards compatibility we return the first in list TURN server directly. This allows clients which do not implement any selection still use TURN and lets the TURN service control which one it should be (first in list is used).
To provide peer to peer support for users with a firewall, a TURN
service might be required. Not everyone can/wants to setup a self-hosted
TURN server. This change adds support to consume a remote TURN service
which usually requires authentication. Spreed WebRTC received TURN
credentials using this service in regular intervals and provides them to
all Spreed WebRTC sessions.
If the remote TURN service provides multiple zones and a GEO location
endpoint, the web client will also directly connect to that TURN service
GEO endpoint to let the TURN service select preferred zones based on the
clients information.
The advanced settings provide a way to control the TURN service zone
directly and to disable the client side GEO call. By default the
selection is auto if the TURN service provides a GEO endpoint. If no
such endpoint is required, the zone with the highest priority is used by
default (as sent by the TURN credentials service).
Simon Eisenmann