Subject: [AVT] Measure of network congestion

From: Alejandro Cabrera Obed <[email-masked]>
Date: Tue, 28 Dec 2004 10:15:16 -0300

Dear People,

Suppose I'll develop an application of HDTV uncompressed on Internet2. 
Suppose I say the app will run only if the network congestion state is
appropriate (i.e., packet loss < 1%).
Suppose I'll use IPERF to measure the packet loss in order to take the
decision to run or not the app.

So, IPERF will measure the packet loss over a given path of the
network, but suppose once I run the app this network path change and
packet loss is greater than 1%.....I ask you: Is it possible to get a
measurement of packet loss with IPERF along all the possible paths of
the end-to-end video connection ??? Otherwise, is it correct to
measure the packet loss along one network path and then affect this
value with a given deviation coeficient I get through several
measurements ???

Thanks and happy new year to you !!!!

Alejandro Cabrera Obed

_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt

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From: David R Oran <[email-masked]>
Date: Wed, 29 Dec 2004 14:38:48 -0500

> decision to run or not the app.
Why not run the app and have it generate the synthetic load and observe 
the RTCP feedback to decide whether to bother with the "important" 
bits? One danger with probes tis that they fail to mimic the real 
traffic with enough fidelity.

> the end-to-end video connection ???
You realize that the number of possible paths is exponential in the 
number of links in the network, don't you?

> Otherwise, is it correct to
to the extent that the load and topology are stable, yes. But the 
interesting cases are when it's not.
> Thanks and happy new year to you !!!!
David R. Oran
Cisco Fellow
Cisco Systems
7 Ladyslipper Lane
Acton, MA 01720 USA
Tel: +1 978 264 2048
Email: [email-masked]