When Capacity Is Never Enough


A bit is a bit is a bit. An electronic packet of data is a packet is a packet. Unless you look inside to see what it contains.

Yet Internet-access providers such as Comcast and Time Warner Cable, the nation’s two largest cable operators, are loath to open the envelopes.

Even if those packets are generated by a relatively small number of users carrying illegally obtained goods — and hogging bandwidth in the process.

“How do you distinguish, without invading the privacy of the people communicating?” asked Federal Communications Commissioner Jonathan Adelstein at last week’s Internet Video Policy Symposium in Washington, D.C. “It’s very hard to distinguish, just looking at packets, whether they’re legal or illegal.”

What Adelstein was talking about was Internet video — and more specifically, the distribution of movies, TV shows and other content by a technique called peer-to-peer sharing.

Broadband Internet-access subscribers use their own computers — and those of anyone who wants to share shows — to manage the distribution of whatever they want to watch. Unchecked, peer-to-peer users have become the bane of network operators, who see no way to limit the ability of these Net-video hogs to usurp the bandwidth they have spent billions to install.

Sharing a single high-definition movie can employ 25 Megabits per second of capacity, until completed. A standard-definition show can take up 6 Mpbs. This isn’t a case for your garden-variety 256,000-bit “broadband” connection anymore.

The solution?

If you’re a policymaker, such as Adelstein, the answer looks like … more bandwidth.

But the answer is not that simple, according to cable-system operators. With peer-to-peer file-sharing, there’s never enough capacity. And broadband network owners would spend huge sums — more billions — to serve the voracious appetites of as little as 5% of their subscribership.


“Video can be a real bandwidth hog sometimes,” Adelstein said Tuesday night. “Of course, one great solution for that problem is adding more capacity.”

If that were accomplished, there would be no debate about the P2P file-sharing problem. You don’t see this kind of problem in Japan, where Internet users are already connected at 100 Megabits per second, Adelstein contends.

But wait. It’s not that cut and dried, according to Comcast. In the face of this form of hogging, there’s never enough capacity. Invest in more bandwidth and, by definition, it will almost immediately be overtaken by file-sharing.

“Because these P2P protocols are designed to devour any and all available bandwidth on the network, it is not possible to build one’s way out of the need for reasonable network management,” Comcast public policy counsel Joseph Waz and a phalanx of other Comcast lawyers argued to the Federal Communications Commission in a Feb. 12 filing of comments on broadband industry practices.

How can that be? It’s relatively straightforward, according to Sena Fitzmaurice, senior director of corporate communications and government affairs for Comcast in the nation’s capital.

The primary program used for efficient distribution of files, BitTorrent, splits tasks between available personal computers. A few central servers “seed” participating PCs with content and those machines, in turn, seed others. In the end, each computer becomes part of a one-for-all, all-for-one union, using a cable network’s last-mile bandwidth to distribute heavy duty content.

To move video or other large files, the seeded computers ask for as much capacity as they can get, to deliver the final result as quickly as possible. And since much of that work takes place in neighborhoods and not network backbones, available capacity is maxed out more rapidly.

When it comes to downloading video for later viewing, as opposed to streaming it for on-demand playback (“I Want My Web TV,” March 17, 2008, page 14), network operators and economic analysts define BitTorrent — and its adherents — as bandwidth hogs.

“It’s a question that answers itself, doesn’t it?” former FCC chief economist Gerry Faulhaber, now a professor at the University of Pennsylvania’s Wharton School of Business, said at the symposium. “It’s not called BitTrickle, after all.”

By one count in the middle of last year, video and audio streaming overtook peer-to-peer applications as the top consumer of Internet bandwidth, accounting for 46% of all traffic. That came after four years of P2P overwhelmingly consuming the most bandwidth, according to Ellacoya Networks.

But even though that report indicated P2P was “losing its status as the biggest bandwidth hog on the Net, that’s not what we’re seeing,” said Yankee Group analyst David Vorhaus. Cable operators continue to report that 60% to 75% of their Internet traffic is being generated by P2P file-sharing, Vorhaus said.

And, as with streaming video, it all boils down to a very small number of outsized users. Vorhaus estimates that 5% to 10% of Internet users are generating 80% to 90% of this P2P traffic. In 2006, research conducted by CableLabs staffer Terry Shaw and Clemson University computer science professor Jim Martin found, in fact, that it only takes about 10 BitTorrent users bartering files on a 500-home network node to double the delays experienced by all other users. That’s especially true if the BitTorrent users are taking in video and everybody else is using “normal priority” services, like e-mail or Web surfing, which are characterized as “best-effort” traffic.

Online, BitTorrent has tried to refashion itself as a legitimate purveyor of video content. Its BitTorrent Entertainment Network, akin to Apple’s iTunes Store, allows legitimate downloads of more than 10,000 movies, TV shows, games and music videos. BitTorrent is marketing its technology to businesses that want to distribute video. Its first client was Brightcove, an online distributor that serves publishers such as Reuters, National Geographic and TMZ.

But Vorhaus, Faulhaber and many other experts believe the vast majority of BitTorrent’s Web traffic consists of content that is being distributed in violation of copyright law. Indeed, 90% of P2P downloads are still of illegally copied content, according to David Hahn, vice president of product management at SafeNet, which tracks the networks.

That means if the capacity of a cable or telephone broadband network were doubled to accommodate more traffic — and such file-sharing continued — it would, in effect, only support further theft.


Not managing this traffic flow could be life-threatening, Faulhaber said. Under a network-neutrality regime, an episode of Baywatch would have the same priority as the transfer of your personal medical history to a hospital the minute you collapse at a restaurant. “Pamela Anderson’s parts are not as important as your heart,” said Faulhaber.

But increasing capacity to support P2P traffic may be inevitable — because legitimate uses of the technology could skyrocket. Using local computers, not just central servers, to distribute video content can be extremely efficient. And if a large, for-profit enterprise such as Amazon or Netflix or Blockbuster or The Walt Disney Co., or all of the above, become heavy users of the technology for video downloads, bandwidth would be under heavy pressure.

“That’s the real concern,” said Vorhaus.

To that point, Comcast has tried to curb the current herd of download hogs by focusing on the uploads that fuel the sharing of files over swarms of personal computers.

To try and limit its network load, Comcast, according to its FCC comments, only manages the uploading of files — at a time when a customer or customers are not downloading files at the same time.

Such “unidirectional sessions” indicate an automated file-sharing process is underway and can be held up until “usage drops below an established threshold” of simultaneous sessions.

This is akin to smoothing out the flow of cars onto a highway through the use of temporary stop lights at on-ramps, Comcast contends.

In effect, Comcast has tried to curb the effects of the use of a P2P application without condemning the application itself. But why?

“Why not target the thing that is causing the problem?” Georgetown Center for Business and Public Policy senior fellow Scott Wallsten said of BitTorrent. “What we have is a problem in waiting.”

Normal network-management technique or not, the Comcast practice of delaying BitTorrent traffic at peak times has prompted scrutiny from the Federal Communications Commission. After the Associated Press called the practice data “blocking,” a coalition of consumer groups and law professors filed a complaint with the FCC. They claimed Comcast had violated the agency’s two-year-old net neutrality policy statement, and should be ordered to stop, as well as fined up to $195,000 per affected customer. Comcast has about 13 million high-speed data subscribers.

“Comcast does not block any Web site, application, or Web protocol, including peer-to-peer services, period,” its executive vice president, David Cohen, responded. “What we are doing is a limited form of network management objectively based upon an excessive bandwidth-consumptive protocol during limited periods of network congestion.”

The commission subsequently opened a formal investigation of the practice; and held a hearing a few weeks ago at the Harvard Law School into the fairness of the practice.

The commission’s chairman, Kevin Martin, says that two troubling aspects of the case are that, in his view, Comcast at first denied the allegations. Also troubling, he said, were allegations that Comcast altered certain user information in packets to effect a delay in peer-to-peer transmissions. He said a ruling will come by July 1.

For its part, Comcast told the commission in its February comments that many of the complaints about the effects of the “blocking” had nothing to do with blocks or delays. Among the complaints: that users couldn’t check e-mail when sending files from home to work and that chat services weren’t working properly, allegedly because of bad network management.

“These commenters’ calls for Commission intervention are misplaced,” Waz and the Comcast attorneys said. “Surely, the Commission has neither the resources nor the ability to turn itself into the help desk for 60 million broadband households.”


The solution again, at first blush, looks like this: Add capacity. Then you could handle all bits equally, without delay.

That “would also deal with the network-neutrality issues. The more capacity, the less of an issue it becomes,” Adelstein said.

But capacity can be a chimera, said Faulhaber. Just look at Japan, a country that Adelstein cites as an exemplar of serving net video hogs and average users at the same time.

Japanese consumers are already used to Internet-access speeds of 100 Mbps — the rate touted by Comcast CEO Brian Roberts at the 2007 Cable Show as the imminent signal speed of “wideband Internet access” from cable operators.

Faulhaber notes that even in Japan, 100 Mbps is not fast enough to avoid the suddenly cardinal sin of managing its network that Comcast has committed.

Even in Japan, delaying the arrival of some content — so-called traffic-shaping — is common. This is a normal practice that allows more efficient traffic processing for all users, not just hogs.

“To say, 'We have a neutral network,’ you never do,” said Faulhaber. You have to be proactive, to give more users more services on a consistent basis, he said.

Telcos like Verizon also face bandwidth scarcity problems from peer-to-peer applications. The problem, however, is more acute for cable, since the upstream bandwidth of a DOCSIS cable modem is just a fraction of the downstream speeds.

Meanwhile, Verizon’s public-relations handling of broadband network management-related issues stands in contrast to Comcast’s.

Earlier this month, the telco announced it has tested a system called P4P, developed by researchers at Yale and the University of Washington, designed to keep peer-to-peer traffic off the Internet’s backbone networks. This technology more intelligently directs P2P traffic to local peers, instead of letting software like BitTorrent try to suck data willy-nilly from all over the world. Verizon claimed that using P4P, 58% of peer-to-peer traffic came from nearby P2P users on its network, compared with 6% before.

Verizon attempted to position the move as an embrace of P2P, pointing out there are legitimate uses of peer-to-peer. In a press release, the telco noted that NBC Universal is using P2P as part of its NBC Direct episode-download service. NBCU has been a critic of P2P networks used to swap copyrighted material, urging the FCC last year to require broadband providers to prevent video piracy.

“No longer the dark-alley distribution system for unauthorized file sharing, advanced P2P delivery networks link content-seekers with licensed files they want,” Verizon’s announcement said.

The cable industry also says it’s working on such engineering solutions to handle P2P traffic with technology suppliers. And that’s how the issues ought be resolved, National Cable & Telecommunications Association CEO Kyle McSlarrow said during a conference call with reporters last Thursday.

“Let the marketplace and the Internet community examine the results of what is, and is not, working,” McSlarrow said.

The management of traffic — and the curbing of bandwidth hogs — is going to get more critical as more types of video unique to the Internet — like feeds from security cameras, or video-rich faux-3D imagery found in such games as the Second Life/Google Earth Web environment Second Earth — emerge.

It’s presumed that Internet video will amount to either narcissistic homemade, personally-focused video or high-end, high-quality professional fare. The real result, though, is likely to be a host of new types of video applications that could only exist with such a low-cost mechanism of worldwide distribution.

The trick, said Faulhaber, is for video content producers to collaborate with distributors to provide a protected channel of high-quality video to legitimate viewers. Otherwise, charging for content will be impossible.

Timing is the problem, said Georgetown’s Wallsten. In essence: Knowing what to do about Net video hogs, and when to do it.

“The Internet changes really fast,” he said. “Policies can’t.”

Todd Spangler contributed to this report.