[AVT] Comments on draft-ietf-avt-rtp-bv-00.txt

[Magnus Westerlund <magnus.westerlund at ericsson.com>]

Hi Raymond,

I have read the draft and have some comments. It is nice to see 
something that is for once simple. I think that after addressing these 
comments you are most likely ready for WG last call. Keep up the good 
work and we can have this done quickly.

1. Page 1: The IPR statement should be part of the Status of this Memo 
section.

2. Please remove the paragraph referencing section 10 of RFC 2026.

3. Section 3.2: first sentence: I think this is normative MAY, please 
change.

4. Section 3.2:
  "To obtain the timestamp of the
   frame that is N frames order than the oldest frame in the packet,
   one simply adds 5*N ms worth of time units to the timestamp of the
   RTP packet."

Is it a spelling mistake, shouldn't "order" be "older"?

5. Section 3.2:
  "The only way
   to determine the number of BroadVoice16 frames is to count the total
   number of octets within the RTP packet, and divide the octet count
   by 10."

For this statement to be correct, you will need to use the RTP payload 
rather then the complete packet.

6. Comment 3, 4, and 5 does also apply to section 4.2

7. section 5. If you try to create such a file from an RTP stream, then 
you would need to have something to put in to indicate lost frames. Does 
there exist any such format, or how should this be done to maintain the 
best quality and synchronization?

8. section 7:
     "-  Any remaining parameters go in the SDP "a=fmtp" attribute by
         copying them directly from the MIME media type string as a
         semicolon separated list of parameter=value pairs."

I think this is an unnecessary statement for this draft, as there exist 
no more parameters.

9. The draft is missing an offer/answer section. Although you does not 
appear to need one, please include one saying that.

10. The draft is missing a congestion control section. I think you can 
suffice with the following blanket statement:

"Congestion control for RTP SHALL be used in accordance with RFC 3550 
[4], and any applicable RTP profile, e.g. RFC 3551 [18].  This means 
that congestion control is required for any transmission over unmanaged 
best-effort networks."

Followed with a declaration that the only way of reducing the bandwidth 
is to pack more frames into the same packet. If that is sufficient, one 
simply has to terminate the session.

11. Section 9: Please update reference [1] and [7] to RFC 3550 and RFC 
3551. don't forget to include the STD notation also.


Cheers

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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