[MMUSIC] Questions on draft-ietf-mmusic-sctp-sdp-05

[Christer Holmberg <[e-mail]>]

Hi,

Section 5.1 of draft-ietf-mmusic-sctp-sdp-05 describes how an offered SCTP association can be rejected, by in the Answer setting the port value in the associated SDP sctpmap attribute to zero.

Q1:         When an SCTP association is rejected, shall the associated port value in the m- line fmt list also be set to zero? The text only talks about the sctpmap attribute.

The draft does not talk about subsequent offers.

Q2:         Do I need to include all sctpmap attributes in subsequent offers, even if some are associated with previously rejected STCP associations, in order to maintain the order?

Q3:         Can I, in a subsequent offer, remove an SCTP association by setting the associated port value to zero? If so, do I set the port value to zero in the associated sctpmap attribute, and/or the m- line fmt list?

The draft only talks about having a single media-subtype per SCTP association.

Q4:         Is it possible to define multiple media-subtypes per SCTP association?

                Example:

                m=application 54111 DTLS/SCTP 5000
              c=IN IP4 79.97.215.79
              a=sctpmap:5000 webrtc-datachannel 16
              a=sctpmap:5000 bfcp 2
              a=sctpmap:5000 t38 1

                (Each media-subtype could use different SCTP streams within the SCTP association)


Thanks!

Regards,

Christer