Subject: [ippm] Fwd: RMCAT SBD

From: David Hayes <[email-masked]>
Date: Thu, 23 Jul 2015 13:43:05 +0200

Hi

I neglected to put the RMCAT list in the original mail. When 
responding, please send to both lists.

Thanks!

David

---------- Forwarded message ----------

 From: David Hayes <[email-masked]>
Subject: [ippm] RMCAT SBD
Date: Wed, 22 Jul 2015 17:19:04 +0200
To: [email-masked]

Hi!

When I presented an update of this work on Shared Bottleneck Detection
(SBD) in the RMCAT meeting a few days ago it was suggested that I send
a note to the ippm group due to the delay metrics the mechanism uses.

The slides for the recent update can be found here:
http://www.ietf.org/proceedings/93/slides/slides-93-rmcat-5.pdf

The draft can be found here:
https://tools.ietf.org/html/draft-ietf-rmcat-sbd-01

The item that prompted this suggestion was the use of a metric
based on Mean Absolute Deviation (MAD).

Some notes on the context of this work:

The mechanism uses summary type statistics describing the shape of
flow OWDs in order to distinguish between flows sharing or not sharing
a common bottleneck. It is designed to be light weight and store a
minimum of state, with potential for having a future OS kernel
implementation (though this is not a requirement or need in the RMCAT
context where it will be in the browser).

MAD (modified to enable 'on the fly' calculation without
storing OWD measurements) is used as a variability measure. It is being
put forward as a more robust measure (for SBD purposes) than the
earlier measure based on a type of PDV measure (max-mean per period T).

The purpose of these measures is for grouping flows not for measuring
performance, however, the use of these metrics may be of interest to
the group. The work may also benefit from the expertise in the ippm
community.

Kind regards,

David

PS

If you are wondering about the examples at the end of the slides
that have significant clock skew and some graph based clustering, these
are work in progress and the mechanisms that facilitates these have not
yet been annunciated in the draft.

-- 

-------------------------
David Hayes
[email-masked]
Department of Informatics
University of Oslo

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