Re: [AVT] I-D ACTION:draft-ietf-avt-tfrc-profile-09.txt

On 10 Jul 2007, at 18:15, Internet-Drafts@ietf.org wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
> This draft is a work item of the Audio/Video Transport Working  
> Group of the IETF.
>
> 	Title		: RTP with TCP Friendly Rate Control
> 	Author(s)	: L. Gharai
> 	Filename	: draft-ietf-avt-tfrc-profile-09.txt
> 	Pages		: 11
> 	Date		: 2007-7-10
> 	
> This memo specifies how the TCP Friendly Rate Control (TFRC) of RTP
>    flows can be supported using the RTP/AVPF profile and the  
> general RTP
>    header extension mechanism.  AVPF feedback packets and RTP header
>    extensions are defined to support the exchange of control  
> information
>    between RTP TFRC senders and receivers. TFRC is an equation-based
>    congestion control scheme for unicast flows operating in a best
>    effort Internet environment.
>
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-ietf-avt-tfrc-profile-09.txt

Reading this, I was surprised that timestamps are specified in  
microseconds, rather than RTP timestamp units. Is there a reason for  
this choice? Using RTP timestamp units would seem easier, since it  
requires only a single clock, and would also allow delta-coding of  
timestamp relative to the timestamp in the RTP header, to reduce  
packet sizes.

The IANA considerations section outlines what is needed in general,  
but needs to be specific about exactly what changes are needed to the  
registries.

The discussion of SDP usage is very limited. I think the draft needs  
to include an Offer/Answer considerations section, explaining how  
this is used in both negotiated and declarative modes. Examples of  
session setup messages using both SIP and (especially) RTSP would be  
useful.

Finally, the idnits tools finds a number of problems, which must be  
fixed before we can progress this draft:

   Checking nits according to http://www.ietf.org/ietf/1id- 
guidelines.txt:
   - No 'Intended status' indicated for this document; assuming Proposed
     Standard

   Checking references for intended status: Proposed Standard
   - Unused Reference: 'RFC2434' is defined on line 391, but not  
referenced
   - Unused Reference: 'RFC3551' is defined on line 400, but not  
referenced
   - Unused Reference: 'RFC4342' is defined on line 423, but not  
referenced
   * Obsolete Normative Reference: RFC 2327
   * Downref: Informational Normative Reference: RFC 4336
   - No information found for draft-ietf-avt-profile-savpf-xx - is  
the name
     correct?
   - Possible downref: Draft Normative Reference: ref. 'SAVPF'
   - No information found for draft-phelan-dccp-dtls-xx - is the name  
correct?
   - Possible downref: Draft Normative Reference: ref. 'ID.DTLS'

     Summary: 2 errors, 8 warnings

-- 
Colin Perkins
http://csperkins.org/

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