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

[Colin Perkins <[e-mail]>]

Qin,

On 20 Aug 2012, at 05:44, Qin Wu wrote:
> Hi,
> ----- Original Message -----
> From: Colin Perkins
> To: Kevin Gross
> Cc: [e-mail]
> 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. 

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