[rtcweb] Constraint to disable IPv6 candidate collection

[Roman Shpount <[e-mail]>]

Hi All,

It is possible to run into interop issues with end-points that support ICE
and DTLS-SRTP but do not support IPv6, such as current versions of Firefox.
Chrome currently offers googIPv6 constraint, which enables or disables IPv6
candidate collection. Unfortunately, this constraint is Chrome specific,
provided via deprecated interface (PeerConnection constructor), and when
this constraint is not set, Chrome collects or does not collect IPv6
candidates pretty much in random. Without setting this constraint, the same
Chrome browser on the same network includes or does not include IPv6
candidates with no identifiable pattern. Because of this, we currently set
googIPv6 constraint to false. Our only other alternative would be to
examine the SDP and remove the IPv6 candidates and replace c= line with
IPv4 address. In anticipation of IPv6 support being enabled by default, and
to avoid SDP mucking, it would be better to define a constraint that can be
used to suppress IPv6 candidate collection, which can be provided via
current constraint interfaces.

_____________
Roman Shpount