On the Long-term Evolution of the Gnutella Network

The popularity of Peer-to-Peer (P2P) file sharing applications has significantly increased during the past few years. To accommodate the increasing user population, developers gradually evolve their client software by introducing new features, such as a two-tier overlay topology. The evolution of these P2P systems primarily depends on (i) coherency across different implementations and (ii) the availability of these feature among clients throughout the system. This paper sheds some light on the evolution of client and overlay characteristics in the Gnutella network during a one year period over which it tripled in size, exceeding two million concurrent peers. Our results show several interesting trends including (i) most users quickly upgrade their software which provides great flexibility for developers to react to changes and (ii) as the system has grown in size the top-level overlay has remained properly connected but there is growing imbalance between the two levels.