A NAT Traversal Mechanism for Peer-To-Peer Networks

NAT (network address translation) are widely used to isolate the private networks from internet. Unfortunately, NATs block the data transmitted directly between two nodes under different private networks in many peer-to-peer applications. A protocol, STUN (simple traversal of UDP over NATs), has been proposed by IETF to solve the problem, but it costs great network bandwidth and transmission delays when the number of nodes is large. In addition, it is less flexible between different network conditions. To solve this problem, this paper makes many practices to improve STUN and proposes a novel NAT traversal technology to establish peer-to-peer connections, enabling load on the sever to be remarkably reduced. Our algorithm called C_STUN classifies nodepsilas area and select proper traversal method dynamically, which can accelerate Nodespsila connection in a large and complicated peer-to-peer network.