Peer NAT Proxies for Peer-to-Peer Games

Network Address Translators (NAT) are ubiquitous on the Internet and any peer-to-peer (p2p) game will almost certainly need to perform NAT traversal through such devices. The authors' experiments suggest that while NAT hole punching techniques are relatively mature, they succeed only about 90% of the time and thus p2p games will inevitably need to employ NAT proxies to establish the remaining connections. They demonstrate with an implementation and a measurement study that using peers as NAT proxies is feasible for both UDP and TCP connections. They found that it is relatively easy to find peers capable of acting as proxies and that the performance achieved is comparable to that of server-based NAT proxies.