Research of TCP NAT Traversal Solution Based on Port Correlation Analysis & Prediction Algorithm

Although solutions have been proposed for NAT traversal in UDP based P2P applications, TCP based NAT traversal still remains challenges due to the relatively complicated protocols. In this paper, we propose a Port Correlation Analysis and Prediction (PCAP) algorithm to predict the NAT allocated port number and a novel PCAP based TCP NAT traversal scheme to build successful P2P connections. We evaluate our method through experiments under real networking environments. The results demonstrate the effectiveness of PCAP algorithm on NAT behavior detection and port prediction and the system achieves higher successful P2P connection rate.