The Research And Design Of P2P Simulator

With the development of the P2P technology, more and more researchers are being engaged in P2P arithmetics.P2P simulators are needed to evaluate new P2P arithmetics before they will be used widely.Some existing P2P simulators are analyzed in this thesis first, then a P2P simulator named PNSim based on .NET framework is designed and implemented.It contains three-layers.They are underlying layer, network layer and overlay layer.In the network layer, which is the middle layer of the three, messages in the overlay layer to be delivered are encapsulated into datagrams and the topology in the underlying layer is taken into account when delivering the datagrams.Besides,the working process of UDP Socket is simulated in the network layer.In the overlay layer, a kind of P2P arithmetic called Chord is implemented and some kinds of methods to simulate nodes' behaviors are provided.In order to make the simulation results more truly, the underlying topology is considered in PNSim.Power-law which can reflect the topology characters of the Internet is studied in this thesis.Two topology models are analyzed and implemented under the guidance of power-law to create topology graphs.In order to create topology graphs reflecting the characters of the Internet more accurately, an improved topology model is given in this thesis.The implementation of PNSim is in accordance with the idea of object-oriented programming.The implementation of the underlying topology models and the P2P arithmetic are encapsulated into some classes and functions.Besides, unified interfaces of method calls are provided to make PNSim support other underlying topology models and P2P arithmetics to be simulated. The functions of PNSim are verified in this thesis.The results show that topology graphs created in the underlying layer can reflect the charcters of the Internet well, and Chord arithmetic was implemented in the overlay layer to support the simulation of the nodes' behaviors.