Research On P2P Network Traversal Strategy And Optimization Method

Peer-to-Peer(P2P)overlay network architecture has been raised much attention since proposed,but deployments of Network Address Translator(NAT)devices make it difficult for nodes to communicate directly.Meanwhile,decentralization and self-organization of P2 P architectures make the entire network vulnerable to be attacked.In order to ensure security,smooth and highquality communications of P2 P nodes,this paper researches on P2 P traversal strategies and secure communication protocols,which improve UDP traversal effectiveness,Qo S and security comparing to traditional traversal strategies and P2 P transport protocols respectively.Firstly,P2 P network architectures are researched in aspects of performance comparison among different P2 P architectures.Based on the researches and analysis above,a network model for session lookup optimization is proposed and its performance evaluations are done.In order to improve Qo S of P2 P network architecture,this paper further studies P2 P traversal strategies and analyses their shortcomings.Considering influences of NAT types,network traffic,and network topologies,we improve traditional traversal strategies,re-classify NAT types,construct its network traffic model,assign NAT communication addresses and traversal methods due to different scenarios and topologies respectively.Experimental results show that the proposed P2 P traversal strategy outperform on accuracy of port prediction,traversal rate and overhead rather than trational strategies.In order to improve security of P2 P network architecture,this paper analayses pros and cons of traditional P2 P communication protocol and raises a novel P2 P secure communication protocol according to DTLS protocol.An acceptor FSM is used to describe state transitions of proposed protocol.Then,communication stages of key negotiation,signature and authenticated encryption are designed and detailed packet formats and communication processes are introduced.Experimental results show that the proposed P2 P secure communication protocol achieves shorter connection establishment time,higher encryption and decryption calculation efficiency.Theoretical analysis proves that the proposed P2 P security communication protocol helps to guarantee the security of communication channels.Finally,the proposed P2 P traversal strategy and the proposed P2 P security communication protocol are applied in P2P-VPN prototype system.Experimental results show that the proposed system can guarantee P2 P communication with high NAT traversal effectiveness and high communication quality.The overall performance meets expected demands,but traversal issues of random symmetric NAT is yet to be researched in the future.