Distributed De Brujin Figure, P2p, Covering Network Design And Analysis

Peer-to-Peer networks(P2P networks) are computer networks by adopting the peer-to-peer model to work,which are products by combining the distributed system and computer network.At present,P2P networks have been widely used in the Internet file-sharing environment. Each P2P node is equal in function,free in action and interconnects in connection, which break out of the traditional client/server model so that all network nodes are equal, free and interconnect,without the difference of the client and server.Due to any two nodes can share file and transmit message in the Internet,P2P overlay networks can greatly increase the network efficiency,make full use of network bandwidth and develop the nodes' potential of P2P networks,which also have very high scalability and good fault tolerance. The rapid development of P2P networks,which has become an important technology and has access to a wide range of academic attention.Because they have accounted for more than half of the current Internet bandwidth resource,they are considered to be "the new network technology changing the Internet".P2P networks are very high efficiency,because the overlay networks with a strict topology built on the top of the network application layer.From the view of design and architecture, the research of P2P overlay networks can be divided into two types:structured and unstructured,they have their respective advantages and disadvantages.The thesis focuses on the structured P2P overlay networks.The structured P2P overlay networks use distributed hash table(DHT) as a substrate accurately and quickly to route information and place data objects.From the study of the topology of structured P2P networks,we found that the performance of structured P2P is related to the underlying static graph.Therefore, according to the difference of static graph,we divide static DHT topology into two types: non-constant degree DHT topology and constant degree DHT topology.Recently,the study of constant degree DHT has attracted great attention of the academic field,especially the compromise research of the average routing length and the size of the routing table.The constant degree DHT is usually built on a certain constant degree static graph.Such as CAN (d-dim.torus),Viceroy(butterfly graph),D2B/Koorde(De Brujin graph),FissonE/Moore (Kautz graph) and so on.These constant degree P2P system,whose performance is not only superior to other non-constant degree P2P system,to a large extent,but also related to the properties of the graph.So from the prospective of the graph theory to study P2P system has become an effective method.In the thesis,we first study P2P system from the prospective of the graph theory and put forward another constant degree P2P overlay networks protocol,which based on the De Brujin digraph.This protocol first modifies the De Brujin digraph,then applies distributed line graph technology into the modified De Brujin digraph in order to construct the structured P2P networks protocol DDBG(Distributed De Brujin Graph).This protocol combines the advantages of the De Brujin digraph and ring structure,making the process of nodes' dynamic join and leave more convenient,improving the fault-tolerance and freedom degree of the network,so it has very high availability.Secondly,from the prospective of graph theory and system topology,we provide a unified graph theoretic analysis framework for the existing structured P2P system and the new P2P system,which combines the properties of graph and the performance of P2P system,and we can also use this framework to guideline the construction of structured P2P system in the future.The thesis mainly is divided into five chapters.Chapter one introduces the development and current situation of P2P networks,then illuminates the core mechanism and enhance mechanism of the P2P system,the structure of the thesis.In chapter two,we study the basic concept of the graph theory,the technology of line graph and distributed line graph, then study the De Brujin digraph and its improvements.In chapter three,a novel P2P overlay networks protocol DDBG(Distributed De Brujin Graph) is proposed.In chapter four,we put forward a unified graph theoretic analysis framework of structured P2P system. In chapter five,we mainly propose some problems to be considered in the future work.