Research And Implementation Of P2P-based Communication Model Applied To Network Education

P2P (Peer-to-Peer) is a kind of network architectures. Computers connect to other computers to share resources and services directly in P2P networks. There are three different structures for P2P networks: Centralized P2P, Structured P2P and Unstructured P2P. P2P solved several types of applications on network: file sharing, P2P computing, search engine, cooperated work and instant messaging.This paper has made research and implementation to a P2P-based network communication model (in short NCM) as the foundation platform of the Network Education System (in short NES). NES that combines school education, society education and family education is the extension of the real school. The communication model is based on Structured P2P architecture. Servers themselves do not deposit any resources. They only help the peers to establish P2P virtual channels and do not relay the data between peers.NCM is divided into four layers: the network layer, the protocol layer, the processing layer and the data layer. The IO completion port enhances the concurrency of the system and the Winsock extensions improve the performance of the network layer. UDP Hole Punching enables two peers to set up a direct P2P UDP session with the help of a well-known rendezvous server, even if the peers are both behind different NATs. Timeout-Retransmission is involved to add Reliability to UDP. The Design Patterns are introduced into the protocol layer to improve the reusability of the code and make the code be easy to maintain and extend. Thread Pool and Memory Pool are used to improve performance of the system.TCP and UDP don't provide the service of data security. An algorithm that combines symmetric encryption with dissymmetric encryption is designed to resolve the problem. We encrypt the key of DES algorithm with the RSA algorithm and the general information with the DES algorithm. The algorithm improves security of the transport in internet.NCM satisfied the Network Education System that is on using now according to tests and it can be used in other OA systems.