Peer-to-Peer Streaming Finds Friends

It's one of the most well-known axioms of streaming: The more popular your content; the more it will cost you. The costs of streaming are such that every new viewer and every new listener adds to your overall costs.

But this basic tenet of streaming is being challenged by a wide range of companies. Recently, companies such as Vingage, Generic Media, Digital Fountain and others claim that they can dramatically lower delivery and hosting costs. Now, a new breed of companies is looking to take advantage of peer-to-peer networks to further lower the costs of streaming.

One company, CenterSpan (www.centerspan.com) announced a peer-to-peer streaming solution last week. CenterSpan is calling this peer-to-peer distribution solution, C-star. Michael Hudson, CTO of CenterSpan said C-star is the secure mediated P2P distribution network that will be added to Scour, the peer-to-peer network it acquired last year.

CenterSpan has "seed peers" which it uses to host and introduce content into the network. Hudson said it also uses an "obfuscated secure cache" that can save chunks of data on a peer's hard drive. Each peer holds a few chunks of data, which are then reassembled during playback. The client software, said Hudson, is only 200KB right now, and will get "slightly larger" with the addition of the streaming server component. CenterSpan licensed the technology from Microsoft, but said that it coded the actual server element itself.

But is the system dependent on the number of peers on a network? "Peer networks definitely need peers, but even if very few peers join, this is cheaper than streaming servers," said Hudson. He said CenterSpan's backend system, which manages and maintains the system looking for the most efficient peers, scales better than traditional streaming systems. "At any moment, we're testing one peer against another and discarding peers," he said. "The network is constantly working to give you the best delivery."

Hudson said that the effects on peer computers are minimal. "We're careful to make sure that the user experience is not one where suddenly the horsepower goes out of your PC," he said. "You don't even notice it's hosting."