NAT Traversal for Pure P2P e-Learning System

In this paper, we present network address translator (NAT) traversal technique suitable for pure P2P applications, such as a distributed asynchronous Web-based training (WBT) system that we have previously proposed. P2P systems have the advantages of scalability and robustness, however, P2P systems face difficulties in constructing its network over the Internet, since end-to-end communication through NATs is sometimes restricted. In this study, as a solution of this issue, we ensure uniqueness of identification of nodes through the Internet and enable to establish a connection over the NAT by means of adding static routing entry to the NAT table with the help of universal plug and play (UPnP). Our NAT traversal technique is implemented in the proposed WBT system and is examined by experiments.