Subject: [Tsvwg] Comments on draft-ietf-tsvwg-diffserv-class-aggr-01

From: "Marvin Krym" <[email-masked]>
Date: Mon, 15 Jan 2007 10:59:53 -0500

The following are my comments on "Aggregation of DiffServ Service
Classes"; draft-ietf-tsvwg-diffserv-class-aggr-01.  This is a resend of
a message from December 20, 2006.

In general the need for an aggregation rule for the DiffSer Service
Classes (rfc4594) is clear especially in core networks.  I agree with
the specific aggregation recommendation and the methodology.  The
following are some specific comments.

1. Figure 2 recommends CS for the treatment aggregate behavior.  Because
the class selector code points have a notion of relative importance,
then a specific CS should be chosen, namely, CS6.

2. Section 4.1.3 contains the recommendation for the assured elastic
aggregate which aggregates CS2 and other AF code points.  From Figure 2,
it appears that CS2 should be treated as AFn1 in the aggregate and if so
this should be made clear in the text.  The treatment for only AFnx
traffic is covered in the text.

3. The EXP markings include 2 codes for the Elastic aggregate behavior
to account for CS0 and CS1.  It seems inconsistent that we would have
one treatment aggregate with one treatment behavior (i.e. Default) yet
define two EXP code points.

Regards
  Marvin