University of Minnesota
University Relations
myU OneStop

Go to unit's home.

Home | Seminars and Symposia | Past seminars/symposia: Wednesday, November 20, 2002

DTC Seminar Series

Integrated System Interoperability Testing with Applications to VoIP


David Lee
Bell Labs Research

Wednesday, November 20, 2002
11:00 am

402 Walter Library

Dr. Lee has been motivated by the need to test interoperability of systems carrying voice calls over the IP network. Voice over IP (VoIP) systems must be integrated and interoperate with the existing Public Switched Telephone Network (PSTN) for them to be widely adopted. Standards have been developed to address this problem, but unfortunately different standards bodies and commercial consortiums have defined different standards. Furthermore, the standards, such as H.323, are often incomplete, complex, and present the implementers with “vendors latitudes.” As a result, there is no guarantee that the integrated VoIP systems would interoperate properly even if the implementations are all H.323-compliant. Interoperability testing has become indispensable. He will discuss criteria that cover all the required patterns of “interoperating behaviors.” Dr. Lee wants to test all such system interoperations. On the other hand, test execution in real environment is expensive, and he wishes to minimize the number of tests while maintaining the coverage. Dr. Lee presents a general method for automatic generation of test cases; it covers all the required system interoperations and contains a minimal number of tests. He studies data structures and efficient test generation algorithms, which take time proportional to the total test case size and report experimental results on VoIP systems. He will report work in progress on state space reduction that preserves system interoperations.


David Lee was born in Hong Kong. He received a master’s degree in Mathematics from Hunter College of City University of New York in 1982. In 1985, he earned both a master’s and a Ph.D. degree in Computer Science from Columbia University. He joined Bell Laboratories Research at Murray Hill in 1985 and became director of Networking Research Department in 1998. He was promoted to Vice President of Bell Labs Research in 1999 and has founded Bell Labs Research China and Asia Pacific in early 2000 and is now on an international assignment of managing the lab. His current research interests include: communication protocol system integration, interface, interoperability and reliability; and all-optical network and next generation Internet protocol systems. He has more than 90 technical publications in journals and referenced conferences and three U.S. patents. David Lee is an IEEE Fellow and won the Distinguished Member of Technical Staff Award of Bell Laboratories Research in 1997. He has won PSTV-FORTE’2000 Best Paper Award in 2000. He is an editor of IEEE/ACM Transactions on Networking, a Senior Editor of IEEE Journal on Selected Areas in Communications, an associate editor of Journal of Complexity, and serves at the Editorial Board of Electronica Sinica. Dr. Lee has also served at various technical program committees of international conferences. He was Program Co-chair of Infocom in 2002, Vice-chair of Infocom in 2001, Program Co-chair of ICNP in 1994 and 2000, General Co-chair of ICNP in 1996, and is Steering Committee Co-chair of ICNP. Dr. Lee has been a Visiting Faculty of National Institute of Standards and Technology (U.S.), Adjunct Professor of Columbia University (U.S.), Visiting Professor of Institute Nationale des Telecommunications (France), Guest Professor of Tsinghua University, Peking University, Fudan University, and Chinese Academy of Sciences (China). He is a Counselor of National Natural Science Foundation of China.