He received the B.E. and M.E. degrees from Kyushu University, Fukuoka, Japan, in 1985 and 1987, respectively. And, he received Ph.D from University of Tokyo, Japan, in 1998.
In 1987, he joined Research and Development Center, Toshiba Corporation, where he engaged in the research of ATM systems. From 1990 to 1991, he has been at Applied Research Laboratory of Bellcore Inc., New Jersey (USA), as a residential researcher. From 1994 to 1996, he has been at CTR (Center for Telecommunication Research) of Columbia University in New York (USA). During his staying at Columbia University, he has proposed the CSR architecture, that is the origin of MPLS(Multi-Protocol Label Switching), to the IETF and to the ATM Forum. From 1996 to 1998, he has conducted the CSR project in Toshiba, as a chief architect.
He is an executive director of IPv6 promotion council, which is cross ministry and cross industry council to promote the IPv6 technology. He is a vice chair of JPNIC (Japan Network Information Center), since 2006, and has served as an IPv6 Forum Fellow. From 2006-2010, he served as BoT(Board of Trustee) for ISOC (Internet Society). He is a director of WIDE Project since 2010, director of Japan Data Center Council since 2009, and director of Green University of Tokyo Project since 2008.