Dynamical Networks: Analysis of P2P Networks

Peer-To-Peer(P2P) networks are becoming ubiquitious.There are different kinds of P2P architectures and each of the architecture has its own merit and demerits. Peers interact and make decisions based on the local information. This local decisions have impact on the global behavior of the network. As a part of this project, first we model the dynamics involved in the network construction phase and then we consider different kinds of p2p architecutes and explore the networks that are formed at the end of network-construction phase. We are interested in the graph properties like: diameter of the network, node clustering and if small world and scale-free properties are exchibited. Studying this would help us comment on the behaviour of the network during its regular P2P operations(resource lookup). Introduction A peer to peer (P2P) network is an overlay network. Unlike traditional client-server model, a peer in P2P network plays the role of both client and server. It acts as a client when it consumes resources of other peers and as a server when its resources are used by the other peers. For ease of resource-lookup all the resourses on the network are mapped onto resourceidentifier space. This is usually done by using some hash-functions. There are different peer-to-peer network architectures. • Centralized Structure:In this architecture, when a peer has some resource to share, it publishes this information on some central server. When it needs to consume a resource on the network, it searches the central server and once the destination-peer is identified, it contacts the destination peer for resource. Here the central-server acts as single source bottleneck. Napster[2] had this kind of architecture. This P2P architecture will not be studied in this project. • Unstructured P2P: Here each peer is connected to some number of random peers. Here there is nothing as distributed index. If a peer has to search for some resource it just floods the network. Gnutella[8] and FreeNet[3] are two such kinds of networks. Here there can be variation where a peers likes to connect to well connected peers rather than some random peers. ∗[email protected]