Subject: [ippm] FW: I-D ACTION:draft-critchley-mlas-reordering-00.txt (fwd)

From: Sam Critchley <[email-masked]>
Date: Wed, 13 Mar 2002 17:36:37 +0100 (MET)

Hi,

I was wondering if anyone got a chance to read this, and if so, if they
have any comments?

Thanks,

Sam

PS Unfortunately I can't be in Minneapolis next week so don't hold your
comments/criticism.... ;-)

---------- Forwarded message ----------
Date: Thu, 07 Mar 2002 12:33:24 -0500
From: Matthew J Zekauskas <[email-masked]>
To: [email-masked]
Subject: [ippm] FW: I-D ACTION:draft-critchley-mlas-reordering-00.txt

cc to ippm didn't make it below...

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On
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Sent: Monday, February 25, 2002 6:23 AM
To: IETF-Announce:
Cc: [email-masked]
Subject: I-D ACTION:draft-critchley-mlas-reordering-00.txt

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title		: Packet Reordering: The Minimal Longest Ascending
                          Subsequence Metric
	Author(s)	: S. Critchley et al.
	Filename	: draft-critchley-mlas-reordering-00.txt
	Pages		:
	Date		: 22-Feb-02

This draft describes a metric, based on the minimal longest ascending
subsequence (MLAS), which can be used to measure the level of
reorderedness of a given single sequence of packets transmitted by one
host and received by a second. This metric enables reordering between
similar packet flows to be compared across differing network
topologies. The draft goes on to provide a set of recommended
parameters which can be used when attempting to consistently compare
reordering, and highlights potential issues which should be taken into
account during measurement.

A URL for this Internet-Draft is:
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From: "Henk Uijterwaal (RIPE-NCC)" <[email-masked]>
Date: Thu, 14 Mar 2002 12:53:40 +0100 (CET)

Sam,

> I was wondering if anyone got a chance to read this, and if so, if they

I did and it looked reasonable in first order.  I've put implementing and
trying it with RIPE NCC TTM data to see if it measures something useful,
on the pile of projects for students for now.

Henk

> implementation to automatically retrieve the ASCII version of the

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Henk Uijterwaal                    Email: [email-masked]
RIPE Network Coordination Centre     WWW: http://www.ripe.net/home/henk
Singel 258                         Phone: +31.20.5354414
1016 AB Amsterdam                    Fax: +31.20.5354445
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That problem that we weren't having yesterday, is it better? (Big ISP NOC)

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From: Sam Critchley <[email-masked]>
Date: Thu, 14 Mar 2002 14:35:35 +0100 (MET)

Hi Henk,

Thanks for the comment. I'd be interested in hearing your progress
with the TTM project.

There's also a subsequence-shift approach which might be worth considering
(see attached). The idea basically being a computationally efficient mode
of calculating the effort required to move each packet in a received
sequence back to its original position in that sequence. It, too, would
seem to work okay. I would be interested in any comments people may have.

It's also worth considering, IMO, whether it's possible to factor loss
into the reordering which a sequence is subjected to..... can you measure
reordering in a sequence in which the same number of packets was not
received as was transmitted?

Many thanks,

Sam

> > implementation to automatically retrieve the ASCII version of the

******************************************************
Sam Critchley           Technology Integration Manager
                        Network Services EMEA
[email-masked]  Worldcom
                       	Joan Muyskenweg 22
Tel: +31 20 711 6082    1096 CJ Amsterdam
                        The Netherlands
******************************************************

---

From: Al Morton <[email-masked]>
Date: Thu, 14 Mar 2002 14:42:39 -0500

Sam,
>received as was transmitted?
You may be answering one of my questions on MLAS, does it require
the complete sequence to use it?
It appears to allow duplicate packets.
Does MLAS require the original sequence numbers to be consecutive?

The definitions in the nonrev and N-Reordering drafts both handle loss.

Al