· Research Director, Extensible Internet, International Computer Science Institute (ICSI)2021–
· Chief Scientist, International Computer Science Institute (ICSI)2012–2021
· Professor Emeritus, Professor in the Graduate School, University of California, Berkeley2004–
· Adjunct Professor, University of California, Berkeley2002–2004
· Networking Group Leader, International Computer Science Institute (ICSI)1998–
· Researcher, International Computer Science Institute (ICSI)1998–
· Adjunct Associate Professor, University of Southern California1995–2001
· Senior Research Scientist, Xerox Corporation (PARC)1995–1998
· Senior Research Scientist, Xerox PARC1995–1998
· Member of Research Staff, Xerox Corporation (PARC)1984–1995
· Member of Research Staff, Xerox PARC1984–1995
· Postdoctoral Researcher, Cornell University1983–1984
· Ph.D. in Physics, University of Chicago1983–
· Sc.B. in Physics, Brown University1978–