Hideo Yoshimi

NAT Traversal Technology of Reducing Load on Relaying Server for P2P Connections

This paper proposes a novel Network Address Translator (NAT) traversal technology to create Peer-to-Peer (P2P) connections through NAT devices, enabling load on the relaying server to be remarkably reduced. The conventional NAT traversal technologies can inflict heavy load on the relaying server because they cannot be applied to NAT devices which randomly assign the port number. In addition, such technologies can overload the relaying server because it must exchange packets with terminals to estimate NAT devices IP address/port number. Our technology estimates the IP address/port number without the relaying server based on a payload checksum of an ICMP message sent back after an investigating packet is transmitted toward a desired peer. Our technology can create P2P connections without inflicting load on the relaying server even in the case where NAT devices randomly assign the port number because it can exactly estimate the assigned port number with only terminal-side processing. This paper clarifies that our technology can reduce more than 80% of the load on the relaying server as compared with the conventional technologies.

Proposal & demonstration of a new remote home-access system, softwire

In this paper, the authors propose a new remote home-access technology, SoftWire, and describe a prototype system in CCNC 2006. Current remote home-access technologies require consumers to know a NAT/Firewall (NAT/FW) IP address and to configure NAT/FW ports to traverse the NAT/FW. This configuration is particularly troublesome for consumers given that changeable IP addresses allocated by DHCP are difficult to be known in advance and the port configuration is not trivial. SoftWire can easily provide a remote home access without NAT/FW’s IP address information and any port configuration by a NAT/FW-traversing scheme based on mail-based callback access. In addition, SoftWire allows consumers to use any application by an Ethernet tunneling scheme based on Ethernet over SSL. In CCNC 2006, we demonstrate the remote home access between US and Japan using SoftWire, and show that it can provide sufficient throughput for various applications including streaming media.