Video killed the ISP?

There's nothing worse than showing up to class only to be confronted by a pop quiz for which you haven't studied, but don't worry; this one will be pretty painless. It's only two questions long. Here's the first one.

Which of the following statements are true of US Internet traffic growth since 2000:

Internet traffic growth has increased exponentially year-over-year Internet traffic growth has held steady year-over-year Internet traffic growth is falling year-over-year

Question number two also concerns Internet traffic growth, but with a special focus on P2P. Hands on your buzzers? Here we go.

Which of the following statements is true of P2P growth over the last several years:

It is growing at 1,553 percent per year It is growing at 690 percent each year It is growing at 100 percent each year

Before we get to the answers, let's consider why the questions matter. A prominent strain of recent argument has claimed that the Internet is headed for an "exaflood" of traffic (which will soon be measured in exabytes), largely coming from the rise of online video, and that the ISPs and backbone providers are in danger of having their levees knocked down. The first question gets to the heart of the issue: are Internet growth rates surging in such a way that Internet providers need to start popping Xanax like it's candy?

The second question is like the first, though with a focus on P2P, which is of course largely made up of video traffic. Comcast and others have asserted to the FCC in the last few weeks that P2P apps are designed to consume all available network bandwidth, that they are an essentially voracious and unstoppable force of carpenter ants that will chew through even the most generous of network upgrades. There is, therefore, no legitimate way to handle the P2P onslaught except through limits, filters, or "delays." The question is whether actual P2P growth rates bear out that assertion.

As traffic increases on the Internet, ISPs and content owners have shown increased interest in blocking, throttling, or limiting it for different reasons. When judging these questions, which bear on network neutrality, Comcast's BitTorrent blocking, and other Internet traffic issues, it's important to start with a solid factual basis. With that in mind, let's turn to the answers.

Surprised to learn that the answer to both questions is number 3? (If not, go make yourself a cup of tea and dig into the cookie jar; you deserve it.) Let's take a look at what the answers mean for the Internet as we come up against the end of the first worldwide Internet decade.

Hurricanes and gales

When Ars last looked at the concept of the exaflood, we concluded that the fear-mongering imagery of a "flood" was overblown and unhelpful to rational debate. It also hid the fact that these sorts of "we're all going to drown in traffic!" stories have been cropping up for years. At the time, I concluded, "Fear of future traffic is an old story on the Internet. It didn't start with 'gigalapses' and it won't stop with the 'exaflood.'"

To get more context on the issue, I sat down with Andrew Odlyzko of the University of Minnesota, one of the top US experts on Internet traffic patterns. Odlyzko runs the Digital Technology Center on campus and also heads up the Minnesota Internet Traffic Studies (MINTS) project, and we met recently at his Minneapolis office to talk traffic trends.



Dr. Andrew Odlyzko

The main point that Odlyzko wants to hammer home from his body of research is that Internet traffic growth is slowing (overall traffic itself is increasing, of course). On the MINTS site, he points out that this can be counterintuitive, even for those in the industry.

"As one striking example," he writes, "at the end of 2005, John Chambers, the CEO of Cisco, claimed that Internet traffic was growing at about 100 percent per year, and similar claims are common. Chambers also predicted both in 2005 and in a keynote at the NXTcomm conference in June 2007 that growth might accelerate towards 300 to 500 percent per year, and that the internal Cisco corporate network traffic load is currently growing at such rates."

But Odlyzko tells me that over the last five years, "traffic growth has been slowing down." In 1995 and 1996, there were periods in which Internet traffic could double in as little as a hundred days, a rate of growth that looked almost terrifying. But it wasn't long before it began to slacken. By the late 1990s, traffic was doubling each year; that is, it was growing at 100 percent a year. But from 2002-2007, the growth rate has dropped, and it now hovers at 50 to 60 percent a year.

That's substantial growth, yes, but it's hardly a flood. Odlyzko tells me that traffic growth is more akin to a gale than a hurricane, and he says that "with a gale, you shorten your sails and you can still steer to some extent." The whole problem with a loaded term like "exaflood" is that "it implies that we're getting overwhelmed, which I don't see happening."

In fact, the Internet backbone has plenty of capacity. If the tubes are going to get clogged, then it's the last mile that will need a good plumber... especially as user-generated content and P2P alter the download-centric model that has undergirded most last-mile network architecture to date.