Academic computer networking started in 1974 in Japan. The Science Information Network covering the whole country operated by the National Center for Science Information Systems (NACSIS) to provide general networking services for academic research purposes since 1986. It consists of a packet switching network based on X.25 over which there exist several virtual networks such as the Inter-university Computer Network, the University Library Network and the High Energy Physics Network, and an Internet backbone network (called SINET) interconnecting campus LANs based on TCP/IP. The number of universities and research institutes participating the Science information network has been increased year by year. By March, 1996, the numbers of universities and research institutes participating the packet switching network and SINET are 237 and 343 respectively.
The Science Information Network has 29 network nodes located in universities from Hokkaido to Okinawa Island. By 1996, the circuits in the domestic network were improved to 150/50 Mbps (12 nodes) and 6 Mbps (17 nodes). An international leased circuit of 2 Mbps linking SINET and EuropaNet via the United States was newly established in July, 1996 and at the same time, the international leased circuit between Japan and the United States were upgraded from 6 Mbps to 8 Mbps, 2 Mbps of which is used to transit Internet traffic between SINET and EuropaNet. Another international leased circuit of 2 Mbps linking Japan and Thailand has been established since September, 1995. From October 1997, the link between Japan and U.S.A. will be upgraded to 45 Mbps.
Since 1994, ATM technology has been introduced to integrate the two networks, which makes it possible for the network to provide high-speed and flexible services and, at the same time, to maintain efficient circuit usage. In 1994, a multimedia multiplexer using ATM technology and frame relay equipment were installed at all 29 network nodes nationally. To meet with the enhanced environment on campuses where ATM-LANs are being introduced rapidly, a new ATM switching system has been procured at each of 29 network nodes in 1996. This new ATM switching system, internally called Multimedia Handling Node, is developed by NTT and has standard interfaces and control functions to connect ATM-LANs. Its official operation started in early October, 1996 with interconnecting campus ATM-LANs by PVCs, and will be upgraded to the operation where SVCs interconnecting ATM-LANs exist very soon.
The SINET support all legacy-type best-effort IP application such as Email, FTP, Telnet and HTTP in conjunction with the new emerging multimedia applications requiring high bandwidth and stringent QoS guarantees. It can provide PVC and SVC services. Currently, UBR PVC-VCC is a major service of PVC services. For SVC services, both DBR and UBR are supported. The SBR and ABR functions have already been installed and will be supported in this network.
In the SINET, a lot of multi-vendor equipment, such as ATM switching systems, routers and frame relay switchers are connected together. Although each piece of network equipment has its own operation system(OpS) to manage the detailed equipment configuration, surveillance, testing/diagnosis and performance monitoring, an integrated network management system(INMS) has been introduced to achieve total and simple end-end network operation and to reduce the network management task and cost. The OpS of each network component is connected to the INMS by using SNMP, and INMS has individual sub management systems for each kind of network equipment.