Subject: RE: [Ieprep] Did anyone get any good testing data of VOIP under network congestion?

From: "King, Kimberly S." <[email-masked]>
Date: Mon, 3 Feb 2003 07:48:38 -0500

Sean said:
>This is a personal opinion, and does not necessarily reflect 
>the views of
>anyone else.

ditto

>For close to 2 years I've been promoting the position we need to deploy
>some VOIP phones, and get experience using them during periods 
>of severe
>network stress.  We need understand what the problems in the real
>world are, while working on things which could improve their 
>performance.

I agree with you and suspect the choice of codecs is extremely important.  

Also, last week I was at a conference and presented some information about
ieprep.  One fellow stood up and said that if networks were under severe
network stress then we should be recommending the use of low-bandwidth
elastic communications such as IM rather than non-elastic non-congestion
aware applications such as VoIP.  It is also a interesting viewpoint.  (See
http://www.saint2004.org/archives/wk6-em/ for the Internet Emergency
Workshop presentations including detailed information about IAA.)

>I was at home, and didn't loose e-mail communications throughout the
>incident. FYI, I'm in California, my personal e-mail is in Maryland.
>So I was criss-crossing the US twice to read my e-mail.  I was 
>exchanging
>e-mail with network engineers around the world throughout the 
>night with
>no noticeble problems.  But e-mail tends to be very elastic.

I think the US didn't experience the most severe problems.  Some of the
Japanese people I spoke with did experience significant problems including
delayed email (although there could be many causes for that.)

>
>Would SIP priority have 
>changed how
>well the VOIP UDP packets got through during periods of severe Internet
>congestion?  

Of course you already know the answer to this.  No, SIP priority markings
can't affect the success of the VoIP UDP packets.  (See James Polk's last
draft illustrating that SIP signaling and media streams take different
paths.)  

The SIP priority could be used at stateful proxies and especially at end
systems like PSTN gateways for an increased probably to resources (if
allowed by policy).

Kimberly
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From: RJ Atkinson <[email-masked]>
Date: Mon, 3 Feb 2003 08:21:49 -0500

On Monday, Feb 3, 2003, at 07:48 America/Montreal, King, Kimberly S. 
> Workshop presentations including detailed information about IAA.)

I agree with that fellow, simply because that approach will maximise the
utility of the network and use of elastic/congestion-avoiding 
applications
is visibly better for the overall health of the network at any time.

Ran