Draft: draft-ietf-rtcweb-jsep

Commentary: Updated to address  's comment 
 I note the following new text : " The IceCandidate object contains a field to indicate which ICE ufrag it is associated with , as defined in < xref target="RFC5245"/ , Section 15.4 . This value is used to determine which session description ( and thereby which gathering phase ) this IceCandidate belongs to , which helps resolve ambiguities during ICE restarts . " Exactly what value does this field contain ? How does one use it to determine to which session description the IceCandidate belongs ?
Paragraph (version A):
As with session descriptions, the syntax of the IceCandidate object
provides some abstraction, but can be easily converted to and from
the SDP candidate lines.
Paragraph (version A):
The IceCandidate object also contains fields to indicate which m=
section it should be associated with.  The m= section can be
identified in one of two ways; either by a m= section index, or a
MID.  The m= section index is a zero-based index, with index N
referring to the N+1th m= section in the SDP sent by the entity which
sent the IceCandidate.  The MID uses the "media stream
identification" attribute, as defined in RFC5888, Section 4, to
identify the m= section.  JSEP implementations creating an ICE
Candidate object MUST populate both of these fields, using the MID of
the associated RtpTransceiver object (which may be locally generated
by the answerer when interacting with a non-JSEP remote endpoint that
does not support the MID attribute, as discussed in sec.applying-a-
remote-desc below).  Implementations receiving an ICE Candidate
object MUST use the MID if present, or the m= section index, if not
(the non-JSEP remote endpoint case).
Paragraph (version B):
In JSEP, ICE candidates are abstracted by an IceCandidate object, and
as with session descriptions, SDP syntax is used for the internal
representation.
Paragraph (version B):
The IceCandidate object contains a field to indicate which ICE ufrag
it is associated with, as defined in RFC5245, Section 15.4.  This
value is used to determine which session description (and thereby
which gathering phase) this IceCandidate belongs to, which helps
resolve ambiguities during ICE restarts.  If this field is absent in
a received IceCandidate (perhaps when communicating with a non-JSEP
endpoint), the most recently received session description is assumed.
Paragraph (version B):
The IceCandidate object also contains fields to indicate which m=
section it is associated with, which can be identified in one of two
ways, either by a m= section index, or a MID.  The m= section index
is a zero-based index, with index N referring to the N+1th m= section
in the session description referenced by this IceCandidate.  The MID
is a "media stream identification" value, as defined in RFC5888,
Section 4, which provides a more robust way to identify the m=
section in the session description, using the MID of the associated
RtpTransceiver object (which may have been locally generated by the
answerer when interacting with a non-JSEP endpoint that does not
support the MID attribute, as discussed in sec.applying-a-remote-desc
below).  If the MID field is present in a received IceCandidate, it
MUST be used for identification; otherwise, the m= section index is
used instead.
Paragraph (version B):
When creating an IceCandidate object, JSEP implementations MUST
populate all of these fields.