[aqm] review of CoDel -00 draft

Wesley Eddy <wes@mti-systems.com> Tue, 17 March 2015 15:45 UTC

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Date: Tue, 17 Mar 2015 11:45:39 -0400
From: Wesley Eddy <wes@mti-systems.com>
Organization: MTI Systems
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Subject: [aqm] review of CoDel -00 draft
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I reviewed and have some comments on the CoDel draft:

1) I believe it would be a good idea to tie the goals listed in
   section 1 (in the bullet list on page 4) to the AQM guidelines
   from the RFC-to-be of draft-ietf-aqm-recommendation.

   Largely, the CoDel goals were brought into that rather than
   being pulled from it, but it will be good to provide a sentence
   or so that ties the working group documents and material together.

2) In the discussion of sojourn time as a metric (section 3.1) and
   using the minimum time to separate good queue from bad queue,
   it struck me that there is some parallel between this and the
   way that LEDBAT works in using the delta from the minimum as
   indication of queues (and congestion) building.  It may be
   worth noting or expanding on delay-based CC in endpoints and

3) Since the algorithm and pseudocode has been published a few
   places before, it would be good to draw attention to a section
   that notes any changes or differences between what will be
   published in this RFC and any other revisions of the pseudocode
   floating around the net (or clearly note if there aren't any).

In generally, it's very readable and I think it would serve as a
clear basis for implementing the algorithm, so would be happy to
see it go forward quickly through this working group to become an

Small / editorial comments:
- The abstract has [TSVBB2011] which doesn't seem to actually
  exist as a reference
- The abstract could really be trimmed to just the 2nd paragraph,
  as the first is just background that's in the Introduction anyways
- The "(covered in another draft)" at the end of section 1 can be
  replaced with a real reference (there's already one later in the
  draft in 4.6)

Wes Eddy
MTI Systems