[aqm] Review of draft-ietf-aqm-codel-07

Fernando Gont <fgont@si6networks.com> Sun, 26 March 2017 03:02 UTC

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Subject: [aqm] Review of draft-ietf-aqm-codel-07
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Reviewer: Fernando Gont
Review result: Ready with Issues

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair.  Please treat these comments just
like any other last call comments.

For more information, please see the FAQ at


Document: draft-ietf-aqm-codel-07
Reviewer: Fernando Gont
Review Date: 2017-03-25
IETF LC End Date: 2017-03-27
IESG Telechat date: 2017-04-13

The document is well written. However, there seem to be too many
details that are left out in other associated documents. Whereas such
details (including figures) are needed to understand this document,
they should be included here. Either provide full explanations or
summarize the outcome without details (there's text that somehow
relies on the reading finding such figures elsewhere).

Major issues:
* Section 5.1, page 16:
>    A more detailed explanation with many pictures can be found in
>    http://www.ietf.org/proceedings/84/slides/slides-84-tsvarea-4.pdf

Unless I'm missing something, if this document is specifying CoDel,
then all such details should be here.

Minor issues:
* General:
The document would benefit from a terminology section. For example,
only well into the I-D one finds definitions of terms such as "sojourn
times" or "target setpoint". Not sure if those terms are supposed to
be trivial/obvious to most people reading this document, but their
non-definition left me trying to figure out what the terms were about
before I was ale to better understand what you were describing.

Page 3, Section 1:
>    o  simple and efficient implementation (can easily span the
>       from low-end, linux-based access points and home routers up
>       high-end commercial router silicon)
There seems to be an unnecesary implicit "judgement" here, associating
linux-based with low-end, and commercial with high end. I suggest you
modify the text.

Page 10:
>            count_ = (delta > 1 && now - drop_next_ < 16*interval_)?

For clarity, I'd use additional parenthesis here.

Nits/editorial comments: 
* Page 17:
>  The power vs. f curve for any AIMD TCP is monotone decreasing. 

Please expand the acronym.

* Page 17:
>    simulation that this result holds for Reno, Cubic, and
>    Westwood[TSV84].

Missing space.