Valid Routing Research Based On P2P Network

Nowadays, Internet system is transforming from the traditional mode of client/server into peer-to-peer(P2P for short) system. The core of P2P is that all participant computer peers(certain computer access to internet) are equal to each other with no difference between client and server. That is, every peer is both client and server, therefore it offers service to other computers and meanwhile share service with others. The concept of P2P was brought forward earlier, but people have paid little attention to it, mainly because there is no practical system as background. It's pervasively accepted by industry and research scholars that such mode of client/server is more reasonable in most cases. With the development of PC skills and Internet, the computing power and bandwidth of PC is enhanced gradually. Accordingly it attracts the most attention how to build a better distributed system by fully utilizing all peers(especially those peers which are former servers).P2P will become an inevitable computing mode in the future, that is, every person contributes his own resources, and shares others'resources meanwhile. P2P mode may be challenged by another grid mode(all resources and service are offered by certain mighty provider, and consumers have to pay to obtain such resources with reassuring service quality). Due to its fine expansibility and taking full advantage of resources, P2P will exist inevitably for long and be applied more extensively.Internationally the researcher teams have made great achievements after penetrating into P2P system to study how to enhance various functions of it. For example Napster, developed in 1999 and then widespread, adopts a centralized directory server where the address's information of every equal peer and saved data information are storing. But Gnutlla, unstructural P2P network which stores data and locate files in a distributed way, developed structured overlay network in 2001 such as Chord, CAN, Pastry and Tapestry, and Distributed Hash Table system. The system is applied to storing system and DNS system, online game, website buffer and newsgroup etc.However many pivotal skills of P2P are still awaiting solutions and improvement, such as topology consistency and resources locating, interoperation, security encryption, QoS and other problems. Hereinto resources searching and locating remains to be the crux of the matter, i.e. how to find out needed resources and service among plentiful scattered peers for consumers. Napster adopts a centralized directory server where the address's information of every equal peer and saved data information are storing. Server will remain the barrier of system with more and more consumers. Gnutllam, unstructural P2P network model adopts a totally distributed strategy to implement data storing and resources locating based on flooding schema, which resembles OSPF routing protocol. This protocol brings about a bigger burden on network communication, and a worse network expansibility on the other hand. DHT also faces series of problems. Based on current DHT routing algorithm, Sylvia Ratnasamy pointed out 15 primary issues facing structural P2P network. He indicated increasing DHT routing efficiency is the keystone of P2P research, and P2P routing capability affects how well P2P is applied. The above-mentioned part shows there exists some deficient and imperfect points concerning P2P algorithm. Therefore this paper beginning with resources locating and searching penetrates into unstructural P2P network and structural P2P network, and suggests improved methods to ameliorate searching by the way of emulate and verification.The main innovations of this paper are as follows:1. We attempt to introduce topology skill into unstructural P2P network, and divide network into clusters and choose super peers according to its own characteristics for more efficient searching and much lighter burden on website. We find unstructural P2P network possesses the characteristics of"Power law"and"Small World", i.e. network of high aggregation. Currently in unstructural network data searching based on flooding is aimless and random. Therefore it's a new attempt to divide network into clusters for data searching based on aggregation.2. We introduce bidirectional storing and data seaching in Chord system based on DHT. In Chord algorithm people have to search data clockwise since data are stored in successive peers. Logically hash values are close to search peers, but anticlockwise, so data cannot be found until the whole peers are searched. Therefore bidirectional storing and data searching will enable to less search hops and delay.3. We construct the emulation system of P2P network to imitate and emulate the improved schema and then come to the emulation result.