QOS or more bandwidth

Kavi, Prabhu prabhu_kavi at tenornetworks.com
Tue May 29 17:30:55 UTC 2001

> -----Original Message-----
> From: Pete Kruckenberg [mailto:pete at kruckenberg.com]
> Sent: Tuesday, May 29, 2001 12:10 PM
> To: nanog at merit.edu
> Subject: RE: QOS or more bandwidth

> Voice-over-IP benefits from statistical multiplexing as
> much, if not moreso, than any other application. A
> toll-quality voice call runs at ~5-6kbps (factoring silence
> suppression and RTP header compression) vs. 8kbps across
> compressed TDM.

Do you mean G.723.1? Let's put aside that some people do not
consider G.723.1 to be toll-quality.  Ignoring that, I would 
call your 5-6 kbps number to be compression rather than 
statistical multiplexing.  The voice packets still come out
periodically every 30ms or so.  The only significant statistical 
multiplexing you get with voice is due to silence suppression.

Also, how do you actually achieve 5-6 kbps when you 
consider the IP overhead?

Prabhu Kavi                     Phone:  1-978-264-4900 x125 
Director, Adv. Prod. Planning   Fax:    1-978-264-0671
Tenor Networks                  Email:  prabhu_kavi at tenornetworks.com
100 Nagog Park                  WWW:    www.tenornetworks.com
Acton, MA 01720

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