Skyscrapers and the Scalability of Gnutella

During today's "What We're Learning from Gnutella" session at O'Reilly's P2P conference, Kelly Truelove gave a brief history of Gnutella and the technology behind it, and put forth a very interesting idea in terms of scalability. He compared Gnutella to a steel-built skyscraper, which has a limit as to how high you can build before it will collapse on itself. In much the same way, this is what happened to Gnutella when it grinded to a halt following the injunction against Napster. Gnutella shouldn't act as one big skyscraper that houses the entire network, but we should think of Gnutella as a series of skyscrapers that make up a city.

This next generation of Gnutella will incorporate better content management rules and drop unresponsive hosts from the network, which would otherwise chew up much needed bandwidth. Those on a dial-up connection connect to a broadband reflector, which is deemed a "super-peer", which is connected to the network, greatly decreasing the amount of bandwidth used across the network due to dissimilar connection speeds.

We've found out how high we can built skyscrapers in the real world, and they are good enough for what we need them for. The challenge now for Gnutella developers is to make the scalability good enough to meet user expectations.