Document..........:  draft-ietf-ippm-delay-var-as-01
Reviewer..........:  Christian Vogt
Review date.......:  Jan. 7, 2009
IESG Telechat date:  Jan. 8, 2009


Summary:  This draft is ready for publication as Informational RFC.


This document compares two widely used metrics for measuring packet delay variations, and it provides guidance with respect to when to use which of the metrics.

I found the document clearly ready for publication.  It is very informative and easy to read.  The comparison and guidelines provided by the document are relevant given the resemblance of the observed metrics and the variety of use cases to which the metrics potentially apply.
Furthermore, the document includes an excellent motivation and survey of related work; this renders it useful for readers of different levels of expertise in the field of performance measuring.  Also, the document is perfectly embedded into existing work through a large number of well-placed references.

Two nits, which should be fixed prior to publication, are the following:

- Section 1.1, 3rd paragraph:  "Lost and delayed packets are separated
   by a waiting time threshold." -- Since the waiting time threshold
   does not only apply to those packets that are lost or delayed, this
   sentence should be rephrased to:  "Packets for which one-way loss or
   delay is measured are...".

- Section 3.2, 4th-to-last paragraph:  "The error in the alignment
   process can be accounted for by a factor, A." -- A is an offset
   (addend) here, not a factor.