A TCP-based Asymmetric NAT Traversal Model for P2P Applications

Network Address Translation (NAT) makes several PCs share a single IP address and is widely used for alleviating the IPv4 address exhaustion. However, when using peer-to-peer (P2P) applications, it is an obstacle for the devices behind NAT to communicate with each other directly basing on the TCP/IP protocol. In this paper, we propose a TCP-based asymmetric NAT traversal model to present hole-punch technique for P2P applications in NAT environment, which uses the existing architecture without any modification. The model can be easily used by most P2P applications, is extensible and does not require additional maintenance.