Design And Implementation Of NAT Traversal Technology In P2P Based On UDP

With the rapid development of Internet technology and a variety of terminal equipment explosive presentation, the network has become an integral part of work life and personal daily. Traditional network address now can not meet the needs of a large variety of network services, while adding the IPv6 address effectively reduce this kind of situation, But at the same time IPv4 to IPv6 transition market still exist a large number of NAT equipment. NAT technology is a rewrite technology when the packet crosses the firewall or a NAT routers and other equipment. NAT Traversal is a through appropriate technical means of establishing a communications link the internal network of different types of NAT to the NAT devices after external networks. Most of the network equipment and terminals such as routers, are now installed or embedded in the NAT device. However, the existence of NAT devices hinders the transmission and sharing of P2 P network resources. How to carry on the NAT penetration under the P2 P environment has become an important issue for people to study.The purpose of this paper is to design and implement a sTURN penetration scheme based on the UDP penetration and the transfer mode as the auxiliary. The scheme includes four modes: P2 P mode, LAN mode, transit mode, and the mode of expansion. The technology is established on the improvement of the classical stun, turn and UDP hole punching technology based, using two types of servers: in NAT external public network server and network internal private network server is to assist the penetration and transmission. This scheme improves the penetration efficiency, reduces the network bandwidth overhead and network transmission delay and balances the load, while avoiding the similar to conventional transit way third-party network server due to network bandwidth and load and other reasons caused by the technology bottleneck. After the success, the same IP/Port is used for TCP data connection and transmission. This system can guarantee in NAT penetration higher success rate and can ensure the reliability in data transmission, better use the UDP and TCP penetration and transmission in the respective superiority. This scheme has good portability, and can guarantee the data transmission quality and user experience.Firstly, the development of architecture and NAT P2 P networks do a brief overview of the analysis and comparison of different network architectures and different models of classic NAT traversal technology advantages and disadvantages, and on this basis, choose a hybrid network based on P2 P NAT penetration and data transmission network topology of technical solutions under the following article gives the overall design of the system, the entire system modules include: initialization, user management, NAT type detection, NAT penetration, data transmission and database. And then were given the detailed design of each module, flowcharts, and part of the code, and in the use of C ++ in windows 7 system network programming so as to realize the program.Then the performance of the system is tested and the results are analyzed. Finally, summarize the main content of the paper,and discussed the scheme in network camera on the subsequent development and application.