Research On Asymmetric NAT Traversal Model

Peer-to-peer network technology is one of hotspot network applications, which has achieved great success in File-Sharing, distributed computation and distributed storage and etc. aspects. However, the network address translation technology which is raised to solve the problems of IP address lack and network security causes the P2P network communication problem. How to solve the problem of traverse NAT for signaling and media stream efficiently will become the key technology for implementation and extension of P2P network.There exists several NAT traversing methods, but each has its limitation. For example, ALG requires that the existing NAT equipment must support the corresponding software update. The STUN method cannot traverse symmetric NAT.In this paper, we propose a NAT traversal model to present hole-punch technique for P2P applications in NAT environment, which uses existing architecture without any modification. The model can be easily used by most P2P applications, is extensible and does not require additional maintenance.The article describes the design of NAT traversal model presented in this paper in detail, and NAT traversal process, and then explain the TCP and UDP-based NAT traversal. Finally we carried out the evaluation of the performance of the NAT traversal method proposed in this paper.