Re: [PMOL] Fwd: I-D Action: draft-sun-tsvwg-flowbased-pm-00.txt

Hi,
I have tried to put together a short review. Please see my comments below (and please provide further comments).

Best regards,
Andreas Johnsson

-----

Comments on draft-sun-tsvwg-flowbased-pm-00.txt.

1) The draft describes a new active measurement protocol with the aim of measuring delay, jitter and loss over an IP path. The protocol is similar to TWAMP (RFC5357), however the measurement setup is performed in a TCP-like manner instead of using a specific control plane. Despite its similarities to TWAMP there are no references nor does the draft contain a comparison. 

2) The draft includes a description on how to calculate statistics based on time stamps obtained by the protocol. The metrics are delay, jitter and loss. An advice is to use RFC 6390 section 5.4.5 guidelines for describing the metrics. 

3) The draft does not reference prior art in IPPM (or elsewhere) related to delay, jitter or loss. Suggested documents are 

IPPM Delay (http://tools.ietf.org/html/rfc2679)
IPPM Loss (http://tools.ietf.org/html/rfc2680)
IPPM Delay variation (http://www.ietf.org/rfc/rfc3393.txt)

ITU-T Y.1540 (http://www.itu.int/rec/T-REC-Y.1540-200711-S)

4) I would like the authors to elaborate on their delay calculation method. The draft assumes that the forward delay is always equal to the reverse delay. How often is this the case?

5) The jitter calculations are based upon the delay calculations. Since the delay is calculated as the RTT (minus the time a packet spends at the PM responder) divided by 2, the jitter will be the same in both directions. Does this really reflect what is happening on the path? Please elaborate on this.

-----Original Message-----
From: pmol-bounces@ietf.org [mailto:pmol-bounces@ietf.org] On Behalf Of Al Morton
Sent: den 29 juni 2012 13:58
To: pmol@ietf.org
Subject: [PMOL] Fwd: I-D Action: draft-sun-tsvwg-flowbased-pm-00.txt

After reading the abstract, I just said "wow".

Would anyone volunteer to review this in a timely way?

Al
pmol admin

>From: internet-drafts@ietf.org
>To: i-d-announce@ietf.org
>Subject: I-D Action: draft-sun-tsvwg-flowbased-pm-00.txt
>X-Test-IDTracker: no
>X-IETF-IDTracker: 4.21p1
>Date: Fri, 29 Jun 2012 01:40:50 -0700
>X-BeenThere: i-d-announce@ietf.org
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>Reply-To: internet-drafts@ietf.org
>
>
>A New Internet-Draft is available from the on-line Internet-Drafts 
>directories.
>
>
>         Title           : Flow-based Performance Measurement
>         Author(s)       : Lishun Sun
>                           Wendong Wang
>                           Fang Yu
>         Filename        : draft-sun-tsvwg-flowbased-pm-00.txt
>         Pages           : 15
>         Date            : 2012-06-29
>
>Abstract:
>    The performance measurements of service flow are becoming significant
>    important for administrators monitoring the fitness of the network.
>    This memo defines an end-to-end application-based performance
>    measurement method, which is achieved by generating synthetic
>    measurement packets, injecting them to the network and analyzing the
>    statistics carried in the measurement packets.
>
>
>The IETF datatracker status page for this draft is:
>https://datatracker.ietf.org/doc/draft-sun-tsvwg-flowbased-pm
>
>There's also a htmlized version available at:
>http://tools.ietf.org/html/draft-sun-tsvwg-flowbased-pm-00
>
>
>Internet-Drafts are also available by anonymous FTP at:
>ftp://ftp.ietf.org/internet-drafts/
>
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