NAT Traversal Techniques in Peer-to-Peer Networks

Peer to peer (P2P) networking has important applications in Internet telephony, online gaming, multimedia communi-cation, instant messaging, file and workspace sharing which raises the need for robust and reliable NAT traversal tech-niques. This paper discusses current and developing tech-niques and challenges posed by NAT traversal in P2P net-works. Initially Network Address Translation (NAT) detec-tion is categorised and both UDP and TCP traversal tech-niques are discussed. Methodologies such as Relaying, Con-nection Reversal, and Hole Punching are then analysed. Fi-nally the development of a testbed is described which can be used to evaluate NAT traversal techniques and to de-termine appropriate configurations in order to achieve P2P networking