Archives for November 2008

With Barack Obama’s election, we’re likely to see a revival of the network neutrality debate. Thus far the popular debate over the issue has produced more heat than light. On one side have been people who scoff at the very idea of network neutrality, arguing either that network neutrality is a myth or that we’d be better off without it. On the other are people who believe the open Internet is hanging on by its fingernails. These advocates believe that unless Congress passes new regulations quickly, major network providers will transform the Internet into a closed network where only their preferred content and applications are available.

One assumption that seems to be shared by both sides in the debate is that the Internet’s end-to-end architecture is fragile. At times, advocates on both sides debate seem to think that AT&T, Verizon, and Comcast have big levers in their network closets labeled “network neutrality” that they will set to “off” if Congress doesn’t stop them. In a new study for the Cato Institute, I argue that this assumption is unrealistic. The Internet has the open architecture it has for good technical reasons. The end-to-end principle is deeply embedded in the Internet’s architecture, and there’s no straightforward way to change it without breaking existing Internet applications.

One reason is technical. Advocates of regulation point to a technology called deep packet inspection as a major threat to the Internet’s open architecture. DPI allows network owners to look “inside” Internet packets, reconstructing the web page, email, or other information as it comes across the wire. This is an impressive technology, but it’s also important to remember its limitations. DPI is inherently reactive and brittle. It requires human engineers to precisely describe each type of traffic that is to be blocked. That means that as the Internet grows ever more complex, more and more effort would be required to keep DPI’s filters up to date. It also means that configuration problems will lead to the accidental blocking of unrelated traffic.

The more fundamental reason is economic. The Internet works as well as it does precisely because it is decentralized. No organization on Earth has the manpower that would have been required to directly manage all of the content and applications on the Internet. Networks like AOL and Compuserve that were managed that way got bogged down in bureaucracy while they were still a small fraction of the Internet’s current size. It is not plausible that bureaucracies at Comcast, AT&T, or Verizon could manage their TCP/IP networks the way AOL ran its network a decade ago.

Of course what advocates of regulation fear is precisely that these companies will try to manage their networks this way, fail, and screw the Internet up in the process. But I think this underestimates the magnitude of the disaster that would befall any network provider that tried to convert their Internet service into a proprietary network. People pay for Internet access because they find it useful. A proprietary Internet would be dramatically less useful than an open one because network providers would inevitably block an enormous number of useful applications and websites. A network provider that deliberately broke a significant fraction of the content or applications on its network would find many fewer customers willing to pay for it. Customers that could switch to a competitor would. Some others would simply cancel their home Internet service and rely instead on Internet access at work, school, libraries, etc. And many customers that had previously taken higher-speed Internet service would downgrade to basic service. In short, even in an environment of limited competition, reducing the value of one’s product is rarely a good business strategy.

This isn’t to say that ISPs will never violate network neutrality. A few have done so already. The most significant was Comcast’s interference with the BitTorrent protocol last year. I think there’s plenty to criticize about what Comcast did. But there’s a big difference between interfering with one networking protocol and the kind of comprehensive filtering that network neutrality advocates fear. And it’s worth noting that even Comcast’s modest interference with network neutrality provoked a ferocious response from customers, the press, and the political process. The Comcast/BitTorrent story certainly isn’t going to make other ISPs think that more aggressive violations of network neutrality would be a good business strategy.

So it seems to me that new regulations are unnecessary to protect network neutrality. They are likely to be counterproductive as well. As Ed has argued, defining network neutrality precisely is surprisingly difficult, and enacting a ban without a clear definition is a recipe for problems. In addition, there’s a real danger of what economists call regulatory capture—that industry incumbents will find ways to turn regulatory authority to their advantage. As I document in my study, this is what happened with 20th-century regulation of the railroad, airline, and telephone industries. Congress should proceed carefully, lest regulations designed to protect consumers from telecom industry incumbents wind up protecting incumbents from competition instead.

Tom Lee wonders about a question that Ed has pondered in the past: how much bandwidth does one human being need?

I’m suspicious of estimates of exploding per capita bandwidth consumption. Yes, our bandwidth needs will continue to increase. But the human nervous system has its own bandwidth limits, too. Maybe there’ll be one more video resolution revolution — HDTV2, let’s say (pending the invention of a more confusing acronym). But to go beyond that will require video walls — they look cool in Total Recall, but why would you pay for something larger than your field of view? — or three-dimensional holo-whatnots. I’m sure the latter will be popularized eventually, but I’ll probably be pretty old and confused by then.

The human fovea has a finite number of neurons, and we’re already pretty good at keeping them busy. Personally, I think that household bandwidth use is likely to level off sometime in the next decade or two — there’s only so much data that a human body can use. Our bandwidth expenses as a percentage of income will then start to fall, both because the growth in demand has slowed and because income continues to rise, but also because the resource itself will continue to get cheaper as technology improves.

When thinking about this question, I think it’s important to remember that engineering is all about trade-offs. It’s often possible to substitute one kind of computing resource for another. For example, compression replaces bandwidth or storage with increased computation. Similarly, caching substitutes storage for bandwidth. We recently had a talk by Vivek Pai, a researcher here at Princeton who has been using aggressive caching algorithms to improve the quality of Internet access in parts of Africa where bandwidth is scarce.

So even if we reach the point where our broadband connections are fat enough to bring in as much information as the human nervous system can process, that doesn’t mean that more bandwidth wouldn’t continue to be valuable. Higher bandwidth means more flexibility in the design of online applications. In some cases, it might make more sense to bring raw data into the home and do calculations locally. In other cases, it might make more sense to pre-render data on a server farm and bring the finished image into the home.

One key issue is latency. People with cable or satellite TV service are used to near-instantaneous, flawless video content, which is difficult to stream reliably over a packet-switched network. So the television of the future is likely to be a peer-to-peer client that downloads anything it thinks its owner might want to see and caches it for later viewing. This isn’t strictly necessary, but it would improve the user experience. Likewise, there may be circumstances where users want to quickly load up their portable devices with several gigabytes of data for later offline viewing.

Finally, and probably most importantly, higher bandwidth allows us to economize on the time of the engineers building online applications. One of the consistent trends in the computer industry has been towards greater abstraction. There was a time when everyone wrote software in machine language. Now, a lot of software is written in high-level languages like Java, Perl, or Python that run slower but make life a lot easier for programmers. A decade ago, people trying to build rich web applications had to waste a lot of time optimizing their web applications to achieve acceptable performance on the slow hardware of the day. Today, computers are fast enough that developers can use high-level frameworks that are much more powerful but consume a lot more resources. Developers spend more time adding new features and less time trying to squeeze better performance out of the features they already have. Which means users get more and better applications.

The same principle is likely to apply to increased bandwidth, even beyond the point where we all have enough bandwidth to stream high-def video. Right now, web developers need to pay a fair amount of attention to whether data is stored on the client or the server and how to efficiently transmit it from one place to another. A world of abundant bandwidth will allow developers to do whatever makes the most sense computationally without worrying about the bandwidth constraints. Of course, I don’t know exactly what those frameworks will look like or what applications they will enable, but I don’t think it’s too much of a stretch to think that we’ll be able to continue finding uses for higher bandwidth for a long time.