The Science Information Network (SINET) is a Japanese academic backbone network for more than 700 universities and research institutions. It connects many research facilities in such fields as seismology, space science, high-energy physics, nuclear fusion, computing science, and so on. It is now being used by over 2 million users and supports international research collaboration through international lines.
SINET4 began operations in April 2011, and it replaces the previous SINET3. SINET4 plays an important role as the core component of the Cyber Science Infrastructure(CSI).