-----Original Message----- From: CAnet-3-NEWS@canarie.ca [mailto:CAnet-3-NEWS@canarie.ca] Sent: Friday, December 01, 2000 2:36 PM Subject: Internet Growth: Myth and Reality, Use and Abuse For more information on this item please visit the CANARIE CA*net 3 Optical Internet program web site at http://www.canet3.net/news/news.html ------------------------------------------- [There has been considerable debate on the issue of Internet traffic growth. I have been guilty as any one of confusing the issue. But I think the following information will clarify some of the confusion. Very simply it is extremely rare when the offered load to the Internet doubles more than once very 7 months. But because of the classic N squared problem of network interconnection the actual network capacity must grow in capacity at a doubling rate of 3 to 4 months to accommodate this growth in offered load. --BSA] Actual Internet traffic growth rates of 100 percent per year are considerably less than the much-ballyhooed doubling every 3 or 4 months. But even these observed rates are still unprecedented and should be provoking new ways of planning. Andrew Odlyzko Andrew Odlyzko is Head, Mathematics and Cryptography Research Department, AT&T Labs - Research, Florham Park, NJ 07932, USA. Dr. Odlyzko has been writing about the evolution of the computing environment for a number of years. He last wrote for iMP in June 2000. http://www.cisp.org/imp/november_2000/odlyzko/11_00odlyzko.htm

Date: Tue, 28 Nov 2000 06:26:22 -0500 (EST) From: mo@UU.NET (Mike O'Dell) To: farber@cis.upenn.edu Subject: 100% per year, etc

Dave,

I see people still don't really understand the difference between offered load (measured as gigabits injected into the edge of the network) and network capacity (measured in gigabit-route-miles of trunking).

This is indeed somewhat subtle and possibly counter-intuitive.

For offered load to double every year, network capacity must double every 4 months or so, at least in our network (UUNET). It is slowing down a some, but that's still pretty fast.

This is actually a pretty simple result from graph theory, once one gets the picture right (as are most results from graph theory - grin).

I admit it took me a while to get the picture right, especially about how to explain what's going on.

Consider an network of two nodes connected by one mile of fiber.

In this network, it's pretty clear that the number of gigabits of offered load should be equal to the number of gigabit-miles of trunking between the two nodes.

Note that it's only the NUMBERS that are equal - the UNITS of the numbers are different. One is gigabits/sec, the other is (gigabits/sec)*miles. This means they can never be *equal*, but the two numbers can grow together - maybe even related by a constant of 1 mile, as in this case.

Now consider a real network.

The network is much more complex than two nodes with one link, and each of those nodes is generating traffic which can go to any arbitrary destination node on a packet-by-packet basis.

In North America alone, there are "35 NFL Cities" which account for a significant fraction of the population (people or computers, take your pick), but there are also many more computers located other places who also wish to have high-performance service. This means the trunking must go a lot of places and be richly connected because...

Every computer expects to reach every other computer with nearly equal quality. While Warhole's Theorem is still relevant, on the Internet you are famous for 15 milliseconds, so who is famous changes very quickly.

The resulting traffic slosh can be very large and the network trunking capacity (gigabit-route-miles) better be in place to handle it or Bad Things(TM) happen.

The result is that for UUNET's network (I can't speak for others) to handle the 100% increase in gigabit/sec offered load over 12 months, the gigabits/sec-route-miles capacity of the network must increase 100% about every 4 months. Again, note the difference in the units of those two numbers.

The planning problem for telephony networks is rather different because the dynamics of telephone calls are so much slower and the data rate required is perfectly predictable.

I dare say that if 800 numbers were routinely "SlashDotted", the outlook of voice network planners would be rather different, and that's ignoring the huge difference in bit-mass moved in the two cases.

The deep intuition about network growth dynamics developed over the years with voice networks simply does not yeild workable results when applied to very large data networks which exhibit huge dynamic ranges of traffic slosh and the astounding doubling of offered load every year. (and this is still the case even given how few people currently enjoy "broadband" access)

So the statements about growth of offered load and growth of network capacity (no matter how much "ballyhooed") are not inconsistent. They are taking about two different but highly interrelated things.

cheers, -mo

======================== Michael D. O'Dell Senior Vice President, Chief Scientist UUNET - the Worldcom Internet Company Room E1-3-117 22001 Loudon County Parkway Ashburn, VA 20147 Voice: +1-703-886-5890 Fax: +1-703-886-5806 Email: mo@uu.net For archives see: http://www.interesting-people.org/

------------------------------------- These news items and comments are mine alone and do not necessarily reflect those of the CANARIE board or management. Bill St. Arnaud Senior Director Network Projects CANARIE bill.st.arnaud@canarie.ca -----Original Message----- From: Sean Donelan [mailto:sean@donelan.com] Sent: Sunday, December 03, 2000 8:05 AM To: amo@research.att.com Cc: nanog@merit.edu Subject: Re: pretty cool paper re "myth of Internet growth numbers" On Sun, 03 December 2000, Andrew Odlyzko wrote:

Since you have have chosen to ignore kc's "meta-operational content warning"

On Sat, 02 December 2000, k claffy wrote:

...

[meta-operational content warning. followup thread probably belongs on some other list]

andrew odlyzko's latest http://www.cisp.org/imp/november_2000/odlyzko/11_00odlyzko.htm

I feel entitled to respond.

First of all, your comments all appear to be based on the paper you cite, namely

http://www.research.att.com/~amo/doc/high.network.cost.txt

This is an entirely different paper on a different subject. (Moreover, just like the article kc cites, it is just a short overview of more detailed papers.) It is sort of like kc saying "Sean's new-born son is cute," and my responding "But his two-year old daughter is ugly." Either statement may be right or wrong, but there is little connection between them.

I skipped over that paper because the basic topic in your paper "Myth of Internet growth Numbers" was covered extensively on this list when the "doubling every 90 days" number was first published a couple of years ago. I think the original source was traced back to a comment made by Mike O'Dell at UUNET. If I recall the conclusion at the time was, at best, the comment was taken very much out of context. You point out that politicians and venture capitalists continue to cite the number to support their projects. Ok, I suppose someone had to say the emperor isn't wearing clothes. But I thought you had some more interesting ideas in the other papers. I think the growth claim is a bit like the last place television channel announcing "they have the fastest growing newscast." It is much easier to double a small number than a large number. But eventually you run out of new viewers. The interesting question isn't why is the Internet acting like a Ponzi scheme. The interesting question is when will the Internet growth curve change from going straight up to an S-shaped curve? Every once in a while, someone will plot the Internet growth curve against the television growth curve, FM radio growth curve, CD player growth curve, etc. The problem is we can't compare them yet, because we don't know where the bend in the Internet growth curve is, yet. So, does you data show the knee was in 1995-1996? Or are we still on the exponential part of the curve? If we are past the knee, its bad news for all the carriers, new and old, since stock price is mostly based on future growth expectation.