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Monday, March 12, 2007 TR10: Peering into Video's FutureThe Internet is about to drown in digital video. Hui Zhang thinks peer-to-peer networks could come to the rescue. By Wade Roush
This article is one in a series of 10 stories we're running this week covering today's most significant emerging technologies. It's part of our annual "10 Emerging Technologies" report, which appears in the March/April print issue of Technology Review. Ted Stevens, the 83-year-old senior senator from Alaska, was widely ridiculed last year for a speech in which he described the Internet as "a series of tubes." Yet clumsy as his metaphor may have been, Stevens was struggling to make a reasonable point: the tubes can get clogged. And that may happen sooner than expected, thanks to the exploding popularity of digital video. TV shows, YouTube clips, animations, and other video applications already account for more than 60 percent of Internet traffic, says CacheLogic, a Cambridge, England, company that sells media delivery systems to content owners and Internet service providers (ISPs). "I imagine that within two years it will be 98 percent," adds Hui Zhang, a computer scientist at Carnegie Mellon University. And that will mean slower downloads for everyone. Zhang believes help could come from an unexpected quarter: peer-to-peer (P2P) file distribution technology. Of course, there's no better playground for piracy, and millions have used P2P networks such as Gnutella, Kazaa, and BitTorrent to help themselves to copyrighted content. But Zhang thinks this black-sheep technology can be reformed and put to work helping legitimate content owners and Internet-backbone operators deliver more video without overloading the network. For Zhang and other P2P proponents, it's all a question of architecture. Conventionally, video and other Web content gets to consumers along paths that resemble trees, with the content owners' central servers as the trunks, multiple "content distribution servers" as the branches, and consumers' PCs as the leaves. Tree architectures work well enough, but they have three key weaknesses: If one branch is cut off, all its leaves go with it. Data flows in only one direction, so the leaves'--the PCs'--capacity to upload data goes untapped. And perhaps most important, adding new PCs to the network merely increases its congestion--and the demands placed on the servers. In P2P networks, by contrast, there are no central servers: each user's PC exchanges data with many others in an ever-shifting mesh. This means that servers and their overtaxed network connections bear less of a burden; data is instead provided by peers, saving bandwidth in the Internet's core. If one user leaves the mesh, others can easily fill the gap. And adding users actually increases a P2P network's power. There are just two big snags keeping content distributors and their ISPs from warming to mesh architectures. First, to balance the load on individual PCs, the most advanced P2P networks, such as BitTorrent, break big files into blocks, which are scattered across many machines. To reassemble those blocks, a computer on the network must use precious bandwidth to broadcast "metadata" describing which blocks it needs and which it already has. |
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Comments
joshcruz on 03/12/2007 at 11:58 AM
2
http://e-convergence.blogspot.com/2007/03/joost.html
http://e-convergence.blogspot.com/2007/02/these-hips-dont-lie.html
http://e-convergence.blogspot.com/2007/01/joost-it.html
http://e-convergence.blogspot.com/2006/12/moves-in-news.html
http://e-convergence.blogspot.com/2006/11/peer-tv-peer.html
lunchtime on 03/12/2007 at 1:34 PM
1
In a P2P network, the physical infrastructure still looks like a tree, but the bandwidth is more efficiently employed because underutilized branches can become content distributors as well as receivers. A P2P network does not increase the total bandwidth available, it just uses the bandwidth better.
In a mesh network, users form new infrastructure by connecting directly (and often through multiple alternate pathes), and the network no longer looks like a tree. A mesh network increases the system's total bandwidth.
Both P2P and mesh networks benefit from "network effects" (i.e., the more users, the better the network), and they are complementary approaches. However, mesh networks have a number of benefits that P2P networks do not, including increasing the resiliency of the network and reducing the control that any ISP can exert over the content distributed on the network and the cost of connection.
muthabroad on 03/12/2007 at 11:40 PM
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jayamannen on 04/30/2007 at 7:46 PM
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In P2P you send your payload/files/streams from anybody to anybody. Isn't that full-mesh?
The signaling doesn't really matter when it comes to bandwidth when the amount of data is big. Just implement an intelligent signaling and then wonder about how much information can be sent now. 100%?
fiberman on 03/12/2007 at 1:50 PM
39
Is it perhaps because the suppliers of products and services for the Internet don't want to free up that bandwidth - it would negatively affect their sales?
Fiberman!
joshcruz on 03/12/2007 at 6:16 PM
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fiberman on 03/14/2007 at 12:07 PM
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I lived thorugh the era 15+ years ago when everybody was saying that the telco protocol ATM would take over all data transfers because it offered compatibility of data with the current voice traffic. Of course, data traffic overwhelmed voice anyway, but ATM lost to IP because 53 byte ATM packets had very poor throughput efficiency with data.
Personally, I think streaming video as IP traffic is insane! Surely others think so too - and are looking at more efficient distribution protocols for streaming video. I know the movie industry is doing work in this area for a private network in LA.
jake3_14 on 03/17/2007 at 12:26 PM
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jayamannen on 04/30/2007 at 8:33 PM
2
Says who?
westqiang on 04/17/2007 at 9:40 PM
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tred on 08/27/2007 at 5:16 AM
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simboy on 08/28/2007 at 11:51 AM
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mpandiar on 10/09/2007 at 1:16 PM
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