Subject: [IMRG] "wish list" of measurement analysis

From: Jennifer Rexford <[email-masked]>
Date: Wed, 25 Sep 2002 12:54:05 -0400 (EDT)

I think it would be useful to put together a "wish list" of unanswered
measurement-analysis kinds of questions -- specific questions that
could be analyzed and/or measurement tools that could be developed.
This would be helpful particularly to graduate students in search of
good research topics.  I can accumulate a list of questions -- just
e-mail to me and I can summarize to the group, or on a Web page.

-- Jen
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From: Victor Reijs <[email-masked]>
Date: Thu, 26 Sep 2002 08:40:19 +0100

Hello Jennifer,

The points would be (see also section 1.3.4 and 1.4 of 
http://www.surfnet.nl/surfnet/persons/reijs/prive/eng/QoSv0.6.pdf):
. get a simple cheap reliable one-way delay measurment tool (I 
know GPS exists but that has some operational problems in some 
rooms and if you want to provided such tools to many people). We 
are now working on NTP or NTP based protocols, but not yet sure 
if they can hadle normal operational environments like (large 
delay variation and assymetric routes).
. a tool for measuring available bandwidth (perhaps pathload will 
work, we are testing this).
. a video quality description based on the network SLS metric. It 
looks as if there is not a real description of video imparements 
due to the SLS metric (delay, delay variation, packet loss, loss 
pattern, avail bandwidth), like available for audio (MOS).
. an accepted/standardized measurement infrastructure that can 
handle all the wishes described in the above document;-)

Hope this helps.

All the best,

Victor

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From: "Henk Uijterwaal (RIPE-NCC)" <[email-masked]>
Date: Thu, 26 Sep 2002 10:45:58 +0200 (CEST)

Victor, others,

> delay variation and assymetric routes).

One way to go here is the timing signal for CDMA phones.  There are now
CDMA based clocks units that will work wherever a CDMA phone will work
(North America, AU, KR, but unfortunately not in Europe).  Since CDMA
phones work inside buildings, this will make installation a lot easier.
We have one such unit under test and the accuracy appears to be as good as
one gets with GPS.  This reduces installation costs to almost 0, so the
OWD tool will the price of a standard PC plus a couple 100 US$.

> work, we are testing this).

So are we.  It appears that the standard implementation (running at the
user level) is very sensitive to other processes running on the machine.
Together with one of Constantinos' students (Joe) we have moved a number
of processes to the kernel level and this seems to improve things a lot.

Henk

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That problem that we weren't having yesterday, is it better? (Big ISP NOC)