Wednesday, July 26, 2006

P2P strikes a leak

I hear rumours from several sources that trials with Kontiki's peer-to-peer technologies by major broadcasters are less than satisfactory.

P2P is fine for file distribution, but works less well in a stateful environment where reliability and quality of service are important. The diagram below shows the differences between unicast, multicast and P2P.



Of course, the more users, the more viable a P2P network, but reliability and quality of service are real issues since the broadcaster has no control whatsoever over the distribution of the content. I have previously pointed to other shortcomings such as using a customer's metered bandwidth and the unreliability of asynchronous connections for high quality streaming.

So what are the alternatives ?

There are really only two choices: getting reasonably rates for unicasting, perhaps by placing distribution nodes within major ISPs' networks; or multicasting, which involves sending the same feed to every viewer - the downside of this is that all the equipment on the network needs to be capable of multicasting for this to work, and, moreover, you loose one-to-one delivery capability.

The original Kon-Tiki might have made it across the Pacific, but her namesake has sprung a leak..

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