Re: [xrblock] proposed change to discard draft for the issue:duplication packet discards

Qin Wu <bill.wu@huawei.com> Wed, 22 August 2012 03:14 UTC

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From: Qin Wu <bill.wu@huawei.com>
To: Colin Perkins <csp@csperkins.org>
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Subject: Re: [xrblock] proposed change to discard draft for the issue:duplication packet discards
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----- Original Message ----- 
  From: Colin Perkins 
  To: Qin Wu 
  Cc: Kevin Gross ; xrblock@ietf.org 
  Sent: Wednesday, August 22, 2012 6:02 AM
  Subject: Re: [xrblock] proposed change to discard draft for the issue:duplication packet discards


  Qin,


  On 20 Aug 2012, at 05:44, Qin Wu wrote:
    Hi,
      ----- Original Message -----
      From: Colin Perkins
      To: Kevin Gross
      Cc: xrblock@ietf.org
      Sent: Saturday, August 18, 2012 12:12 AM
      Subject: Re: [xrblock] proposed change to discard draft for the issue:duplication packet discards


      Kevin,


      On 17 Aug 2012, at 18:11, Kevin Gross wrote:
        I don't think it is necessary or appropriate to include this sort of value judgement. What is expensive? What is necessary? At best, this is getting tangential. I support the original wording of Qin's note though I think it should be a separate paragraph and perhaps marked as a note.


      Qin's original wording seems to me to be encouraging duplication. I do not support that, since it does break RTCP statistics if done in the naïve way implied. I'm happy if someone wants to propose a more neutral wording, part-way between my suggestion and Qin's text.

    [Qin]: How about rephrasing it as follows:
    "
    Note that duplicating RTP packets is for robustness or error resilience but may disrupts RTCP statitics.
    In order to tackle this, the mechanism described in [draft-ietf-avext-rtp-duplication-00] can be used which
    will not cause breakage of RTP streams or RTCP rules.
    "
    This statement will put as an indepent paragraph as Kevin suggested.


  The "may disrupt RTCP statistics" is misleading: duplicating RTP packets in the naïve manner _will_ break RTCP. 

[Qin]:Okay, how about removing "may" from the proposed text?


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