[78943] in North American Network Operators' Group
Re: Clearwire May Block VoIP Competitors
daemon@ATHENA.MIT.EDU (Mikael Abrahamsson)
Sat Mar 26 14:56:10 2005
Date: Sat, 26 Mar 2005 20:55:42 +0100 (CET)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: nanog@merit.edu
In-Reply-To: <Pine.CYG.4.58.0503261303580.3448@citabria>
Errors-To: owner-nanog@merit.edu
On Sat, 26 Mar 2005, Adi Linden wrote:
> 90kbps may be low bandwidth but the packets per second are a killer for
> some equipment. VoIP typically has small packets, 80 bytes or 160 bytes,
> whereas your webbrowser has most packets close to the max MTU, usually
> 1500 byte packets. There is quite a bit of wireless gear that buckles
> under the stress of very few VoIP streams. Those few streams add up to
> much less then the theoretical advertised throughput.
A typical voip call is a packet in each direction every 20ms, this makes a
total of 100pps.
Translated into a tcp stream with one ack per data packet, this would mean
600 kilobit/s bandwidth usage with the same pps. I would be quite upset if
I couldn't use 600 kilobit/s for approximately the same time I would use
voip per day (which truthfully wouldnt be much).
--
Mikael Abrahamsson email: swmike@swm.pp.se
