Re: [aqm] [iccrg] Follow-up: PIE performance in cable modem environments

John Leslie <> Fri, 03 May 2013 23:53 UTC

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Date: Fri, 03 May 2013 19:53:45 -0400
From: John Leslie <>
To: Greg White <>
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Subject: Re: [aqm] [iccrg] Follow-up: PIE performance in cable modem environments
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Greg White <> wrote:
> I did a diff on the new version of the PIE code vs the earlier release
> and found, as you stated, that the basic algorithm hasn't changed.
> I do see some other improvements/changes though. One which, I think,
> bears discussion is the weighting of packet drops based on size.
> In the new code there is the option (turned on in the simulations I
> reported on in my paper) to drop packets according to
> p*pkt_size/mean_pkt_size where p is the drop probability calculated by
> the PIE control law. This serves to significantly decrease the drop
> probability of the small VoIP and gaming packets, which may be
> sensitive to loss (from a QoE perspective) and non-responsive to loss
> (from a congestion control perspective).  This is evidenced by the low
> packet loss rate for gaming traffic that I reported in my paper.
> However, I worry that the unintended consequence may be that this
> weighting incentivizes application developers toward the use of small
> packets, which seems ill advised.

   The IESG has approved for publication as an RFC:

which, basically, says "Don't do that".

John Leslie<>