Re: [xrblock] Fw: I-D Action: draft-ietf-xrblock-rtcp-xr-discard-05.txt

Glen Zorn <glenzorn@gmail.com> Fri, 27 July 2012 01:51 UTC

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From: Glen Zorn <glenzorn@gmail.com>
To: Alan Clark <alan.d.clark@telchemy.com>
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Date: Fri, 27 Jul 2012 08:51:00 +0700
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Subject: Re: [xrblock] Fw: I-D Action: draft-ietf-xrblock-rtcp-xr-discard-05.txt
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On Thu, 2012-07-26 at 07:25 -0400, Alan Clark wrote:

> Because packet discard often results from high levels of jitter/PDV


Sorry, I guess that I was _way_ too terse :-(; please allow me to
explicate:

             1. The acronym "PDV" is not expanded or used anywhere else
                in this document; given this, it's usage seems more like
                an afterthought than an integral part of the draft.
             2. There is, however, another WG draft discussing PDV
                reporting in some detail (although the acronym is never
                explicitly expanded in that document, either).  The
                proposed text says "Early/ late discards are usually
                regarded as a symptom of PDV due to congestion (or route
                changes)" which suggests that at least sometimes such
                discards are not a result of PDV.  Might it not be a
                good idea to be able to check the correlation (if any)
                between the number of earl/late discards and the level
                of jitter?  If so, maybe it would be a good idea to both
                reference draft-ietf-xrblock-rtcp-xr-pdv and suggest
                sending along the Packet Delay Variation Metrics Block
                as well.
                

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