Presence and IntComm WG

["Enyeart, Mike" <>]

The speed of light means that to circumnavigate half way around the
earth will take approx 200 ms. As long as jitter is minimal, I have
found that 300 ms is fine.

-Mike Enyeart

-----Original Message-----
From: 

 
[mailto:]
On Behalf Of Jeremy George
Sent: Thursday, October 23, 2003 8:38 AM
To: Guy T Almes
Cc: Ben Teitelbaum; 
;
 VoIP Working Group
Subject: Re: Real and Non-Real Time Traffic (was [WG-PIC:352] Re: FMM
demo notes)

Guy,

>   I'd love to hear more from you and the others in wg-pic and wg-voip
about 
> the specifics of how amount of queueing delay and stability of
queueing 
> delay impinge on their work.

  ITU-T specifications cap mouth-to-ear delay at 150ms for toll quality
voice.  How much of that can be allocated to transmission depends on
the hardware being used for the terminal devices.  A guideline might be
100ms.

  Jitter is often noted as a culprit but RTP timestamps will smooth
over modest delivery variability.  The key is timely delivery within
the ~100ms window.  If that can't be accomplished, we are better off
(as Sally Floyd points out) not sending the bits in the first place.

- Jeremy

>   One quibble: I would not want to burden your effort too early, but I

> would argue that congestion control will be needed if/when large-scale

> deployment occurs.  The cute way of saying it is that you only need to
do 
> it if your application succeeds.

  I agree that the congestion control elements of real time transmission
within our purview, the UAs, should be addressed within the PIC and
VoIP working groups.  And I don't think it's too early or too hard to
begin doing it now.

- Jeremy


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