Re: [rtcweb] draft-ietf-rtcweb-jsep-05 - Recycling m-lines

[Paul Kyzivat <[e-mail]>]

Section 5.2.2 (Subsequent Offers) says:

    o  If a m= section was rejected, i.e. has had its port set to zero in
       either the local or remote description, it MUST remain rejected
       and have a zero port in the new offer, as indicated in RFC3264,
       Section 5.1.

That 3264 reference is to a section about the initial offer, and so is 
irrelevant to the case. The relevant section is:

    8.1 Adding a Media Stream

    New media streams are created by new additional media descriptions
    below the existing ones, or by reusing the "slot" used by an old
    media stream which had been disabled by setting its port to zero.

IOW, previously rejected m-lines may be recycled.

Later in 5.2.2:

    o  If a m= section exists in the current local description, but has
       its state set to inactive or recvonly, and a new MediaStreamTrack
       is added, the previously existing m= section MUST be recycled
       instead of creating a new m= section.  [OPEN ISSUE: Nail down
       exactly what this means.  Should the codecs remain the same?
       (No.)  Should ICE restart?  (No.)  Can the "a=mid" attribute be
       changed?  (Yes?)]

This seems to assume that there is no existing MediaStreamTrack for 
these m-lines.

If there is, then
- the m-line shouldn't be recycled.
If there isn't, then
- where do its address and port come from?
- what is managing the RTCP?

	Thanks,
	Paul