Why Gnutella Can't Scale. No, Really.

That summer we all saw a rush of press on Gnutella, and the rumour mill started churning. Most stories covering Gnutella were grossly and inappropriately evangelical, praising the not-yet-analyzed Gnutella as a technology capable of delivering on wildly fantastic promises of fully distributed, undeterrable, unstoppable, larger-than-life file sharing on the grandest scale. Many folks were convinced that Gnutella was the . Gene Kan, the first to spearhead the Gnutella evangelical movement, claimed in one early interview: "Gnutella is going to kick Napster in the pants." Later Kan admitted "Gnutella isn't perfect", but still went on to say that "there's no huge glaring thing missing". Well, something just wasn't right, and though we couldn't see it, it did seem pretty glaring. We all understood the excitement. Herein was a technology that could potentially prove the true magnitude of Metcalfe's Law. That realization evoked nothing short of the phrase . But what I couldn't understand was why no one was questioning the legitimacy of these claims. For several months the only analyses anyone heard of practical implementations were generalizations and speculative comments, without much scientific or mathematical basis. So I quickly got fed up, and resolved to write a research paper. Sometime in late March, I had begun analyzing the network structure of the Gnutella system, trying to find a way to gauge the capacity of a GnutellaNet in generalized terms, and to predict its realistic limits. What later resulted was a set of mathematical equations that could describe reachability, capacity, and bandwidth throughput. I then fed those equations into Mathematica to produce 3-D plots depicting, much to my own satisfaction, visual realizations of exactly what didn't make sense At about the same time, a fellow colleague in the security industry wrote a short paper detailing the various and flagrant insecurities inherent in