Yes, but most companies do not want to upgrade the access link to unneeded levels just to ensure that VOIP never has contention. It is on the access link where QOS matters, ingress and egress. That is where we (AT&T) have deployed it and where it makes sense. It's not about pitting one customer's traffic against another's across the core. The core is over-provisioned for high bandwidth and simplicity. It is pitting one customers applications against their other applications. It is about large packets (1500 byte) vs. small VOIP packets. It is about getting the VOIP out the door while less sensitive applications wait in queue if that is what is required on the access link. It is usually about T1 and below. Michelle Michelle Truman CCIE # 8098 Principal Technical Consultant AT&T Solutions Center mailto:mtruman@att.com VO: 651-998-0949 (NEW NUMBER) w 612-376-5137 -----Original Message----- From: Valdis.Kletnieks@vt.edu [mailto:Valdis.Kletnieks@vt.edu] Sent: Monday, February 10, 2003 12:23 PM To: Charles Youse Cc: Bill Woodcock; nanog@nanog.org Subject: Re: VoIP QOS best practices On Mon, 10 Feb 2003 13:02:39 EST, Charles Youse <cyouse@register.com> said:

That doesn't seem to make a lot of sense - is it that QoS doesn't work as advertised?

Qos is designed for dealing with "who gets preference when there's a bandwidth shortage". Most places are having a bandwidth glut at the moment, so the VoIP traffic gets through just fine and QoS isn't able to provide much measurable improvement.