He received the B.E. and M.E. degrees from Kyushu University in 1985 and 1987, and received Ph.D from the University of Tokyo in 1998. In 1987, he joined Toshiba Corporation. From 1990 to 1991, he has been at Bellcore Inc., New Jersey (USA), as a residential researcher. From 1994 to 1996, he has been at Columbia University (USA).
He is a president of JPNIC (Japan Network Information Center), an IPv6 Forum Fellow, a director of WIDE Project, a vice president and a chairman of steering commitee of Japan Data Center Council, a director of Green University of Tokyo Project, a chairman of JNSA (Japan Network Security Association), a chairman of IPTV Forum, a chair of CSA Japan, the first Chief Architect of Digital Agency Japan.