Interesting People mailing list archives
The Great IP Debate
From: David Farber <dave () farber net>
Date: Tue, 13 Jul 2004 09:07:40 -0400
Begin forwarded message: From: Tom Fairlie <tfairlie () frontiernet net> Date: July 13, 2004 8:28:45 AM EDT To: dave () farber net Subject: Re: [IP] The Great IP Debate Hi Dave, I posted a similar response here about 2 years ago, but it bears repeating. VoIP, even though I used to be a fairly good architect of VoIP systems, really doesn't stack up to legacy circuit-switched circuits for voice. First of all, VoIP adds all of those headers. For a normal G.711 (64 Kbps) channel, you really need about 114 Kbps of bandwidth to handle the IP, UDP, RTP, etc. header info. Of course, you don't need G.711. You could use G.728 or whatever to increase compression. Unfortunately, the quality--which is already low--will then sink to the level of cell phone traffic. This might be fine for you, but I'd rather see an improvement for the investment--not a decline. Then, you can save bandwidth by doing header compression. Unfortunately, VoIP will require encryption overhead, so this is in most cases a wash. On top of that, in order to achieve the quality of service (QoS) that we have today, you will have to use one of the insufficient (DiffServ, RSVP) or cumbersome (MPLS) technologies that reduce the overall bandwidth flexibility of the new network and essentially create an ad hoc, circuit-switched network out of it. Economically, does it really make sense to build a brand new network with brand new equipment and then saddle it with a host of protocols and management schemes that make it quack just like the network we have today that's already paid for? It really makes me wish that ATM had truly taken off 10 years ago. ;-) Tom Fairlie ----- Original Message ----- From: "David Farber" <dave () farber net> To: "Ip" <ip () v2 listbox com> Sent: Tuesday, July 13, 2004 6:43 AM Subject: [IP] The Great IP Debate Begin forwarded message: From: Randall <4whp () insightbb com> Date: July 12, 2004 10:23:08 PM EDT To: Dave Farber <dave () farber net> Subject: Re: [IP] The Great IP Debate On Mon, 2004-07-12 at 07:41, David Farber wrote:
In addition, carriers have invested so much in their legacy voice networks that many hesitate to move voice traffic from the legacy network to an IP platform. "Circuit switched is not going away. It's a legacy system that will be with us for a long time," says John Marinho, vice president of marketing and offer management at Lucent's Mobility Group. "But VoIP is the cornerstone that will enable a lot of things to be possible in the next several decades."
In 1979, Dr. Jerry Maren stood in front of my CIS 100 class and said "Punch cards are Yesterday's News, but if any of you hope to get jobs working with computers, you will be working for banks, governments or insurance companies, because that's where the computers are. Those people have invested millions of dollars in punch card technology, and they're not going to just throw those card readers away - so you're going to learn how to use punch cards, even though they will be gone in twenty years or so." ------------------------------------- You are subscribed as tfairlie () frontiernet net To manage your subscription, go to http://v2.listbox.com/member/?listname=ipArchives at: http://www.interesting-people.org/archives/interesting-people/
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