[55759] in North American Network Operators' Group
RE: VoIP QOS best practices
daemon@ATHENA.MIT.EDU (Ray Burkholder)
Mon Feb 10 14:49:35 2003
Date: Mon, 10 Feb 2003 14:21:50 -0500
From: "Ray Burkholder" <ray@oneunified.net>
To: "Charles Youse" <cyouse@register.com>,
"Alec H. Peterson" <ahp@hilander.com>
Cc: <nanog@nanog.org>
Errors-To: owner-nanog-outgoing@merit.edu
G.711 gives you the 64kbps quality you get on a channel in a PRI line.
No compression is performed.
G.729 is a well accepted codec that performs compression, and with ip
packet overhead, uses about 16 to 24 kbps (can't remember which). It
gives voice quality very close to G.711.
G.723 has a noticeable voice quality change, and is in the 6 to 8 kbps
range.
The optimal is G.729 for quality vs bandwidth issues.=20
There are some other considerations involved but these are the main
ones.
Ray Burkholder
> -----Original Message-----
> From: Charles Youse [mailto:cyouse@register.com]=20
> Sent: February 10, 2003 14:42
> To: Alec H. Peterson
> Cc: nanog@nanog.org
> Subject: RE: VoIP QOS best practices
>=20
>=20
>=20
> Speaking of codecs, what are the primary variables one uses=20
> when choosing a codec? I imagine this is some function of=20
> how much bandwidth you want to use versus how much CPU to=20
> encode the voice stream.
>=20
> C.
>=20
> -----Original Message-----
> From: Alec H. Peterson [mailto:ahp@hilander.com]
> Sent: Monday, February 10, 2003 1:40 PM
> To: Bill Woodcock; Charles Youse
> Cc: nanog@nanog.org
> Subject: RE: VoIP QOS best practices
>=20
>=20
> --On Monday, February 10, 2003 10:19 -0800 Bill Woodcock=20
> <woody@pch.net>=20
> wrote:
>=20
> >
> > It works fine on 64k connections, okay on many 9600bps=20
> connections. T1 is
> > way more than is necessary.
>=20
> I'd say that largely depends on which codec you are using and=20
> how many=20
> simultaneous calls you will have going.
>=20
> Alec
>=20
> --
> Alec H. Peterson -- ahp@hilander.com
> Chief Technology Officer
> Catbird Networks, http://www.catbird.com
>=20
