Last Call Review of draft-ietf-aqm-codel-07
review-ietf-aqm-codel-07-secdir-lc-nir-2017-03-21-00

Hi,

I have reviewed this document as part of the security directorate's ongoing
effort to review all IETF documents being processed by the IESG.  These
comments were written primarily for the benefit of the security area directors.
 Document editors and WG chairs should treat these comments just like any other
last call comments.

The document describes the CoDel (controlled delay) framework for reducing
bufferbloat. It does a good job of describing the problem, outlining the
solution and providing both a description of the algorithm (including
pseudo-code) and linking to real world implementations.

Two nits:

1. A lot of terms are used long before they are explained, such as Estimator,
Sojourn time, Interval (BTW: if this is a moving interval the spec should
probably say so). When reading sections 3 I concluded that the document was
aimed at peopel who already knew all these terms and didn't need definitions,
but then reading section 5 gave me a lot of a-ha moments about what I had read
previously.

2. The security considerations section says "There are no specific security
exposures associated with CoDel."  CoDel is about dropping packets, so
immediately I have to think how I could subvert a router running CoDel to drop
other people's packets. Perhaps it is fine to say that there are no known
attacks on CoDel and no steps necessary to mitigate such, but I think it's
tempting fate and hackers to say that CoDel has no security exposures.