Stanford P2P Group Releases Software and Analysis

Bert690 writes "Apropos of yesterday's Slashdot story on BitTorrent: Some folks at Stanford have released a paper on P2P "bucket brigade"-like streaming that contains *an actual analysis* and a downloadable implementation." Could this be considered actual research on the subject of p2p networks and scalability?

Comments

Re:P2P Research

[EricKrout.com]

With all due respect, your statement There is lots of P2P Research going on is about as dumb as saying "There was a lot of relational database research in the 1970s".

P2P is the latest big hit in the software/networking realm. Email's old-school these days, the Web's getting tiresome, but P2P is THE exciting new technology.

Doesn't utilize upload capacity of leaves

[bramcohen]

Any tree-based distribution mechanism has no way of utilizing the upload capacity of it's leaves, resulting in a huge amount of wasted capacity.

The reason to have a tree structure rather than a mesh structure is, quite simply, that a mesh structure is a lot harder to implement.

BitTorrent, which I'm the author of, does a mesh properly. It also has real-world deployment experience - it held up against slashdotting quite well. Thanks go out to everyone who's downloaded using it.

I'm a bit skeptical of their claims of robustness and QoS. I have real experience with the way real machines behave on the net, and trying to get real-time streaming working before you've even got file transfer going seems like putting the cart way before the horse.

There's also the issue of interrupts when peers higher up in the tree drop out or become slow, and then there's leeching problems...

As for doing simulations, I'd love to have a way of doing simulations which was at all useful, but my experience has been that real-world net churn and congestion behavior is just so funky that back-of-the-envelope calculations are as good as you're gonna get.

Re:Doesn't utilize upload capacity of leaves

[Anonymous Coward]

It isn't surprising that robustness and QoS may be easier to achieve for real-time streaming networks than for file transfer; real-time streaming imposes more constraints on the client than does "plain old" file transfer.

In the real-time streaming scenario, clients are restricted to accessing the content synchronously (or close enough). All clients access the same content at the same time and have no say in what content comes out of the source. Thus, real-time streaming networks have a large pool of 'volunteer' routers to draw from when a disruption occurs.

In the file transfer scenario, clients access content asynchronously. The network is less homogenous, so file transfer networks have more difficulty reconfiguring themselves when a node leaves a network. Extra flexibility in the client translates into more complex, less reliable networks.