The draft is easy to read and understand.
1. Section 5.2, "Service Codes", refers to DCCP service codes. Several are
defined in this specification (SC:RTPA, SC:RTPV, SC:RTPT, and SC:RTPO). The
draft needs to say something about the relationship between the SDP media
type field (the "audio" and "video" of m=audio and m=video) and the DCCP
service code -- I expect they SHOULD match.
2. I wonder if an optimization would be useful, where
"a=dccp-service-code:SC:RTPV" is assumed if the associated media type is
"video" (m=video); a similar optimization seems reasonable for audio (RTPA
is assumed when the media type is audio (m=audio)).
3. I believe the draft needs to define a value for its IANA-registered DCCP
service codes, as service codes appear to be sent in the DCCP packets
themselves according to RFC4340.
4. I'm surprised a=rtcp (RFC3605) lacked normative language in section 5.1.
I know for UDP this is widely considered best practice. I'm not confident
that we should expect DCCP will be able to avoid that quagmire. I suggest
adding something like:
If RTCP is to be sent on a separate DCCP connection
to RTP, the RTCP connection SHOULD use the next higher destination
port number, unless an alternative DCCP port is signalled using the
"a=rtcp:" attribute . For improved interoperability, "a=rtcp"
SHOULD be used whenever an alternative DCCP port is used.
> -----Original Message-----
> From: Cullen Jennings [mailto:fluffy@xxxxxxxxx]
> Sent: Thursday, June 07, 2007 1:31 PM
> To: MMUSIC WG
> Subject: [MMUSIC] Fwd: Last Call: draft-ietf-dccp-rtp (RTP
> and the DatagramCongestion Control Protocol (DCCP)) to
> Proposed Standard
> I would like to point out this last call is happening - if you have
> opinions on the SDP usage in this draft - do not reply to
> this email.
> Reply on the IETF list.
> Begin forwarded message:
> > From: The IESG <iesg-secretary@xxxxxxxx>
> > Date: June 6, 2007 7:18:36 AM PDT
> > To: IETF-Announce <ietf-announce@xxxxxxxx>
> > Cc: dccp@xxxxxxxx
> > Subject: Last Call: draft-ietf-dccp-rtp (RTP and the Datagram
> > Congestion Control Protocol (DCCP)) to Proposed Standard
> > Reply-To: ietf@xxxxxxxx
> > The IESG has received a request from the Datagram Congestion Control
> > Protocol WG (dccp) to consider the following document:
> > - 'RTP and the Datagram Congestion Control Protocol (DCCP) '
> > <draft-ietf-dccp-rtp-06.txt> as a Proposed Standard
> > The IESG plans to make a decision in the next few weeks,
> and solicits
> > final comments on this action. Please send substantive
> comments to
> > the
> > ietf@xxxxxxxx mailing lists by 2007-06-20. Exceptionally,
> > comments may be sent to iesg@xxxxxxxx instead. In either
> case, please
> > retain the beginning of the Subject line to allow automated sorting.
> > The file can be obtained via
> > http://www.ietf.org/internet-drafts/draft-ietf-dccp-rtp-06.txt
> > IESG discussion can be tracked via
> > https://datatracker.ietf.org/public/pidtracker.cgi?
> > command=view_id&dTag=15015&rfc_flag=0
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