A scale-free and self-organized P2P overlay for massive multiuser virtual environments

Massive Multiuser Virtual Environments have recently grown popular, and commercial virtual online worlds like Second Life or World of Warcraft attract a lot of attention. In this context, for the research on distributed systems, especially the idea of a 3D Web as a global scale virtual environment is very interesting, since it poses severe technical challenges to the underlying infrastructure. It is generally accepted, that the realization of such a global scale scenario can not be realized in a traditional centralized fashion. For this reason in the course of the HyperVerse project we have developed a two-tier Peer-to-Peer (P2P) architecture as basic infrastructure for a federated and scalable 3D Web. Our approach relies on a concept, that incorporates a loosely-structured P2P overlay of user clients and an overlay that connects a federation of reliable server machines constituting a reliable backbone service. This paper proposes a self-organized and scale-free network overlay for the reliable backbone in the HyperVerse architecture. The overlay incorporates advantages of scale-free networks, self-organization and epidemic aggregation in order to tackle the severe challenges of the scenario in a fully distributed fashion without any central control.