ICE/TURN - Investigate why relay candidates are most often selected
It has been observed in many environments when TURN relay is enabled, that the ICE negotiation will frequently result in relay candidates (TURN) being selected while server-reflexive or peer-reflexive candidates should have been selected instead. Typically, when the "connectivity checks" succeed for both relay and reflexive candidates, the reflexive candidates should be selected because of their higher priority.
Note that in the current version, the "Aggressive nomination" is used to optimize the connection time (see RFC5245 for more details). This may have a major impact on the selected pair. Still, we need to know if this is the only cause or if other factors are involved. We also need to know if we can improve it.