While looking at ICE, TURN, and QoS interactions I am struggling with a
scenario that I would like to see if others have any thoughts on.
The driver for this is a desire to ensure necessary overhead for STUN
Data/Send Indications are accounted for in QoS allocations prior to an
active destination being set by the UA.
ICE does not appear to provide any guidance on when the UA should set
the active destination. Section 12.1.1 of ICE talks about interactions
with SIP and requires that no media be sent till a valid candidate for
each component has entered the valid list. If the valid candidate is a
relayed candidate and media begins to flow, should the UA first set the
active destination or send the media wrapped in a STUN Send Indication
and only set the active destination at some later point in the call
flow? I would think you want to set the active destination as soon as
possible to avoid the extra overhead, but was unsure what the
implications of such an approach might be. If the expectation is to
always set the active destination prior to sending media, then the QoS
calculations would not need to account for any additional overhead.
Is there a case where media would begin flowing but the UA would be
unable to set the active destination?