Nerve Net: A Regional-Area Network for Resilient Local Information Sharing and Communications

Information and communications systems in Japan were badly damaged by the great earthquake and tsunami on March 11, 2011. Their importance as societal infrastructure was recognized strongly. Since 2006, NICT has been developing a resilient network, called Nerve Net. It is a regional-area network for access to the Internet and for resilient information sharing and communications even if the access is impossible in emergency situations. It is composed of multiple base stations interconnected each other by using a variety of Ethernet-based wired or wireless transmission systems as optical/metal Ethernet, WiFi, FWA, satellite, and unmanned aerial vehicle (UAV), configuring a mesh-topological network. Each base station consists of a LAN switch and a CPU board for controlling the switch, providing packet transmission and applications using distributed database among all the base stations over a mesh network. Compared with existing Internet-depend, tree-topological network systems, Nerve Net is tolerant to link disconnections and system failures because of mesh structure and fast route switching on layer 2, and is able to continue providing applications such as phone, messaging and information sharing without a connection to the Internet because each base station has functions of DHCP, DNS, SIP proxy, and mobility management. 30-basestation-scale test bed has been operated more than one year and a pilot test has started in Onagawa town, Miyagi prefecture, hit by the tsunami.