The Great IP Debate

[David Farber <dave () farber net>]

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."



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