Education

Post Doctoral Studies, Computer Science, Institute for Advanced Computer Studies, University of Maryland, USA, September 1990

Ph.D., Computer Science, The Center for Advanced Computer Studies, University of Louisiana, USA, July 1988. Dissertation Title: A Unified Approach to Performance Evaluation of Dataflow and Multiprocessing Architectures.

M.Sc.(Engg.), Dept. of Computer Science and Automation, Indian Institute of Science, Bangalore, India, December 1985. Thesis Title: Multiprocessing Architectures for Parallel Hidden Surface Removal Algorithms.

B.Tech., Dept. of Electrical Engineering, Indian Institute of Technology, Kanpur, India, May 1983.

Professional Experience

July 2004 – Present: Professor, Department of Computer Science, University of California, Davis CA 95616.

July 1998 – Present: Associate Professor, Department of Computer Science, University of California, Davis CA 95616.

July 2000 – November 2000: Co-founder iScale Inc., Mountain View, California

November 1995 – June 1998: Assistant Professor, Department of Computer Science, University of California, Davis CA 95616.

September 1990 - November 1995: Member of the Technical Staff, Bell Communications Research, Red Bank, New Jersey 07701, USA.

September 1988 - August 1990: Research Associate, Institute for Advanced Computer Studies, The University of Maryland, College Park, MD 20742, USA.

July 1986 - July 1988: Research Assistant, The Center for Advanced Computer Studies, University Louisiana, Lafayette, LA 70504, USA.

January 1986 - July 1986: Teaching Assistant, Department of Computer Science, University of Southwestern Louisiana, Lafayette, LA 70504, USA.

August 1983 - December 1985: Research Fellowship, Department of Computer Science and Automation, Indian Institute of Science, Bangalore, India.

Research Interests

P2P Networks, IP Telephony, Cellular Networks, Wireless Ad Hoc Networks, Sensor Networks, Distributed Systems, Performance Evaluation

Journal Publications

Stephen Mueller, Rose P. Tsang, and Dipak Ghosal, “Multipath Routing in Mobile Ad Hoc Network – Issues and Challenges,” Invited paper. To appear in Lecture Notes in Computer Science, 2004.

Dipak Ghosal, Benjamin Poon, and Keith Kong, “P2P Contracts: A Framework for Resources and Service Exchange" accepted for publication in the special issue of Future Generation Computer Systems, 2004

S. Kovvuri, V. Pandey, B. Mukherjee, D. Ghosal, and D. Sarkar, ``A Call-admission Control (CAC) Algorithm for Providing Guaranteed QoS in Cellular Networks," Intl. Journal of Wireless Information Networks, 2003, to appear {Preliminary version: S. Kovvuri, V. Pandey, D. Ghosal, B. Mukherjee, and D. Sarkar, ``A call-admission control (CAC) algorithm for providing guaranteed QoS in cellular networks,'' Proc., IEEE Wireless Access Systems, San Francisco, CA, Dec. 2000}.

W. Wen, B. Mukherjee, S.-H. Gary Chan, and D. Ghosal, ``LVMSR-- An efficient algorithm to multicast layered video," Computer Networks, March 2003 {Preliminary Version: W. Wen, S.-H. Gary Chan, D. Ghosal, and B. Mukherjee, ``LVMSR--An efficient algorithm to multicast layered video,'' Proc., IEEE ICC 2000 conference, New Orleans, LA, pp. 254-258, June 2000.}

B. Reynolds and D. Ghosal. STEM: Secure Telephony Enabled Middlebox. IEEE Communications Magazine Special Issue on Security in Telecommunication Networks. October 2002.

M. C. Caesar and D. Ghosal. IP Telephony, Invited paper, Encyclopedia on Telecommunications, 2002, Wiley InterScience.

J. Escorcia, D. Ghosal, and D. Sarkar, ``A Novel Cache Distribution Heuristic Algorithm for a Mesh of Caches and its Performance Evaluation,'' Computer Communication, Vol. 25, February 2002, pp. 329-340.

J. Kidambi, D. Ghosal, and B. Mukherjee, ``Dynamic Token Bucket (DTB): A Fair Bandwidth Allocation Algorithm for High-Speed Networks,'' Journal of High-Speed Networks (2001) {Preliminary Version: S. Kovvuri, V. Pandey, D. Ghosal, B. Mukherjee, and D. Sarkar, ``A call-admission control (CAC) algorithm for providing guaranteed QoS in cellular networks,'' Proc., IEEE Wireless Access Systems, San Francisco, CA, Dec. 2000. }

K. Kong and D. Ghosal, “Mitigating Server-Side Congestion in the Internet Through Pseudo-Serving,” in IEEE/ACM Transactions on Networking, August 1999.

J. Jue and D. Ghosal, “Design and Analysis of a Replicated Server Architecture for Support of IP-Host Mobility,” Accepted for publication in Cluster Computing Special issue in Mobile Computing 1998 (Preliminary version: J. Jue and D. Ghosal, “Design and Analysis of Replicated Servers to Support IP-Host Mobility in Enterprise Networks,” Proceedings ICC '97, June 1997.).

K. Kong and D. Ghosal, ``Pseudo-Serving: A User-Responsible Paradigm for Internet Access,'' Computer Networks and ISDN Systems, Vol. 29, 1997, pp. 1053-1064 (Preliminary version: K. Kong and D. Ghosal, ``Pseudo-Serving: A User-Responsible Paradigm for Internet Access,'' Proceedings of the 6th International World Wide Web Conference, Santa Clara, April 1997, pp. 546-557.).

Dipak Ghosal, T.V. Lakshman and Yennun Huang, “Parallel Architectures for Processing High-Speed Network Signaling Protocols,” IEEE/ACM Transactions on Networking, Vol. 3, No. 6, December 1995, pp. 716-728 (Preliminary version: Dipak Ghosal, T.V. Lakshman and Yenun Huang, “High-speed Protocol Processing Using Parallel Architectures,” IEEE INFOCOM 1994, Toronto, Canada, June 1994, pp. 159-166 Vol.1).

Pietro Manzoni, Dipak Ghosal and Guiseppe Serazzi, “Impact of Mobility of Data Transport Protocols: An Integrated Performance Study,” IEEE Journal on Selected Areas in Communications, Special Issue on Mobile and Wireless Computing, Vol. 13, No. 5, June 1995, pp. 858-867 (Preliminary version: Pietro Manzoni, Dipak Ghosal and Guiseppe Serazzi, “A Simulation Study on the Impact of Mobility on TCP/IP,” 1994 International Conference on Network Protocols, Boston, Massachusetts, October 1994, pp. 196-203.).

Jonathan Chao, Dipak Ghosal, Debanjan Saha and Satish K. Tripathi, “IP over ATM Local Area Networks,” IEEE Communications Magazine, August 1994 Vol. 32, No.8, pp. 52-59 (Preliminary version: Debanjan Saha, Dipak Ghosal and Jonathan Chao, “A Design for Implementation of Internet Protocol in a Local ATM Network,” International Communication Conference, New Orleans, 1994, pp. 1326-30, Vol.3.).

T.V. Lakshman and Dipak Ghosal, “Performance Evaluation of an Efficient Multiple Copy Update Algorithm,” IEEE Transactions on Parallel and Distributed Systems, February 1994, Vol. 5, No. 2, pp. 217-224 (Preliminary version: T. V. Lakshman and Dipak Ghosal, “Performance Evaluation of a Symmetric O(/N) Multiple Copy Update Algorithm,” Symposium on Parallel and Distributed Systems, Dallas, Texas, December 1991, pp. 488-495.).

T.-H Wu, H. Kobrinski, Dipak Ghosal and T.V. Lakshman, “The Impact of SONET Digital Cross-Connect System Architecture on Distributed Restoration,” IEEE Journal on Selected Areas in Communications, January 1994, Vol. 12, No.1, pp. 79-87.

Sarit Mukherjee, Satish K. Tripathi and Dipak Ghosal, “A Multi-class Priority-Based Slotted Ring LAN and its Analysis,” IEEE Transactions on Computers, August 1993, Vol.42, No. 8, pp. 1015-1020.

Dipak Ghosal, Ramki Thurimella, Yacov Yesha, and Amar Mukherjee, “Scheduling Task Trees onto a Linear Array,” Journal of Computer and Software Engineering, 1997 (Preliminary version: Dipak Ghosal, Amar Mukherjee, Ramkrishna Thurimella and Yacov Yesha, “Mapping Task Trees onto Linear Arrays,” 1991 International Conference on Parallel Processing, Chicago, August 1991.).

Dipak Ghosal and Laxmi N. Bhuyan, “Performance Evaluation of Dataflow Computers,” invited book chapter in Dataflow Computing: Theory and Practice, Edited by John A. Sharp, Ablex Publication Corporation, Norwood, NJ, 1992.

Qing Yang, Dipak Ghosal and Satish K. Tripathi, “Performance Study of Two New Protocols for Voice Data Integration on Ring Networks,” Computer Network and ISDN Systems, 23(4):267-286, January 1992.

Dipak Ghosal, Guiseppe Serazzi and S. K. Tripathi, “Processor Working Set and its Use in Scheduling Multiprocessor Systems,” IEEE Transactions on Software Engineering, May 1991, Vol.17, No.5, pp. 443-453.

Yuan-Bao Shieh, Dipak Ghosal, Prasad R. Chintamaneni and Satish K. Tripathi, “Modeling of Hierarchical Distributed Systems with Fault Tolerance,” IEEE Transactions on Software Engineering, April 1990, Vol.16, No.4, pp. 444-457 (Preliminary version: Yuan-Bao Shieh, Dipak Ghosal and Satish K. Tripathi, “Modeling of Fault-Tolerant Techniques in Hierarchical Systems,” 1989 Fault Tolerant Computing Conference, Chicago, June 1989. Another preliminary version: Yuan-Bao Shieh, Dipak Ghosal, Prasad R. Chintamaneni, and Satish K. Tripathi, “Application of Petri Net Models for the Evaluation of Fault-Tolerant Techniques in Distributed Systems,” 1989 IEEE Distributed Computing Conference, June 1989.).

Dipak Ghosal and Laxmi N. Bhuyan, “Performance Evaluation of a Dataflow Architecture,” IEEE Transactions on Computers, May 1990, Vol.39, No.5, pp. 615-627.(Preliminary version: Dipak Ghosal and Laxmi N. Bhuyan, “Analytical Modeling and Architectural Modification of a Dataflow Computer,” Proceedings 14th Annual International Symposium on Computer Architecture, Pittsburgh, PA, June 1987, pp. 81-89.).

Laxmi N. Bhuyan, Dipak Ghosal and Qing Yang, “Approximate Analysis of Single and Multiple-ring Networks,” IEEE Transactions on Computers, July 1989, Vol.38, No.7, pp. 1027-1040 (Preliminary version: Dipak Ghosal, Qing Yang and Laxmi N. Bhuyan, “Analysis of Multiple Token-ring and Multiple Slotted-ring Networks,” Proceedings IEEE Computer Networking Symposium, Washington D.C., November 1986, pp. 79-86.).

Dipak Ghosal and L. M. Patnaik, “SHAMP: An Experimental Shared Memory Multimicroprocessor System for Performance Evaluation of Parallel Algorithms,” Microprocessing and Microprogramming, No. 19, 1987, pp. 179-192.

Dipak Ghosal and L. M. Patnaik, “Parallel Polygon Scan Conversion Algorithm: Performance Evaluation on a Shared Bus Architecture,” Computers & Graphics, Vol.10, No.1, 1986, pp. 7-35.

Journal & Conferences (Under Review)

James E. Burns and Dipak Ghosal, ``Automatic Detection and Control of Media Stimulated Focussed Overloads,'' Under review in Telecommunication Systems.

Xiao-yan Fang and Dipak Ghosal, “Characterizing the delay across a GSM/GPRS Network,” IEEE Transactions on Vehicular Technology.

Vijoy Pandey, Xiaoxin Wu and Dipak Ghosal and Biswanath Mukherjee, Quantifying the Benefits of Handoff Queuing in a Multitier Cellular Network, IEEE Journal on Selected Areas in Communication.

Vijoy Pnadey, Dipak Ghosal, and Biswanath Mukherjee, Exploiting User Profiles to Support Differentiated Services in Next Generation Wireless Networks, IEEE Network Magazine.

Julee Pandya, Prasant Mohapatra, and Dipak Ghosal, Exploiting Ad-hoc Networks for Efficient Cache Invalidation Schemes in Mobile Environments, IEEE Wireless Communications and Networking Conference 2004.

Jennifer Yick, Archana Bharatidhasan, Gregory Pasternack, Biswanath Mukherjee, and Dipak Ghosal, “Optimizing Placement of Beacons and Data Loggers in a Sensor Network - A Case Study,” IEEE Wireless Communications and Networking Conference 2004.

Vijay Ponduru, Biswanath Mukherjee, and Dipak Ghosal, Coverage-Aware Multipath Routing in Wireless Sensor Networks, IEEE Wireless Communications and Networking Conference 2004.

Dipak Ghosal, Brennen Reynolds, Chen-Nee Chuah, and S. Felix Wu, Vulnerability Analysis and A Security Architecture for IP Telephony, Multimedia Technologies and Services Symposium, 2004

Referred Conferences & Workshops

X.-yan Fang and D. Ghosal, Performance Modeling and QoS Evaluation of MAC/RLC Layer in GSM/GPRS Networks, ICC 2003 General Conference - Networking, May 2003.

B. Reynolds and D. Ghosal, Secure IP Telephony using Multi-Layer Protection, The 10th Annual Network and Distributed System Security Symposium, San Diego, California, February 2003.

V. Pandey, D. Ghosal, and B. Mukherjee, ``Pricing-based Call Admission and Handoff Control in Wireless Networks," Proceedings., World Wireless Congress (WWC '03), San Francisco, CA, May 2003.

J. Abramson, Xiao-yan Fang, and D. Ghosal. Analysis of an Enhanced Signaling Network for Scalable Mobility Management in Next Generation Wireless Networks. IEEE Globecom. Taiwan, ROC, November 2002.

V. Pandey, D. Ghosal, and B. Mukherjee, ``Exploiting User Profiles to Support Differentiated Services in Next-Generation Wireless Networks," Proc., Intl. Conf. on Personal Wireless Communications (ICPWC '02), New Delhi, India, Dec. 2002.

M. C. Caesar, D. Ghosal, and R. H. Katz. Resource Management for IP Telephony Networks, Tenth International Workshop on Quality of Service (IWQoS 2002). Miami Beach, May 15-17, 2002.

X. Wu, D. Ghosal, and B. Mukherjee, ``Benefits of queued handoff in a multi-tier architecture,'' Proc., IEEE Globecom 2000, San Francisco, CA, pp. 1396-1401, Dec. 2000.

V. Pandey, D. Ghosal, and B. Mukherjee, ``Performance Issues in Two-Tier Cellular Networks,'' Proc., IEEE Intl. Conference on Personal Wireless Communications (ICPWC '99), Jaipur, India, pp. 374-378, Feb. 1999

Todd Sinclair and Dipak Ghosal, “An Enhanced Signaling Network Architecture for Replicated HLR Databases,” International Communication Conference (ICC), Vancouver, June 1999.

Arijit Mukherjee and Dipak Ghosal, “Impact of Background Traffic on the Effectiveness of FEC-based Schemes for Packet Audio over the Internet,” International Teletraffic Congress, June 1999.

Dipak Ghosal, “A Case Study of the Tradeoffs in a Parallel Protocol Processing Architecture Under Transient Link failures” in IEEE International Computer Performance and Dependability Symposium, Durham, NC Sept. 7-9, 1998.

V. Pandey, D. Ghosal, and B. Mukherjee, ``Channel Allocation Strategies in Two-Tier Cellular Networks,'' Proc., 9th IEEE Workshop on Local and Metropolitan Area Networks, Banff, Canada, pp. 394-399, May 1998.

Dipak Ghosal, Gopal Mempat, and Tsong-Ho Wu, “Performance and Fault-Tolerance Analysis of a Replicated HLR Placement Strategy,” Accepted in International Conference on Personal and Universal Communications, September 1998.

Jason Jue and Dipak Ghosal, “Design and Analysis of a Replicated Server Architecture for Support of IP-Host Mobility,” in ACM Mobility and Computer Communication Review (MC2R), July1998.

Boning Feng, Dipak Ghosal, and Narana Kannappan, “Impact of ATM ABR Control on the Performance of TCP-Tahoe and TCP-Reno,” Proceedings Globecom 1997, Phoenix, November 1997.

Boning Feng and Dipak Ghosal, ``Comparison of TCP-Tahoe and TCP-Reno over ATM ABR,'' Presented in the 6th IFIP ATM Workshop, Bradford, UK, July 1997.

James E. Burns and Dipak Ghosal, ``Automatic Detection and Control of Media Stimulated Focussed Overloads,'' Proceedings of the International Teletraffic Congress, Washington D.C., June 1997, pp.889-900.

Dipak Ghosal, “Performance and Fault-Tolerance of Database Management Scheme for PCS,” An International Conference on Computer Networks, Architectures and Applications, January 1995, Madras, India.

Dipak Ghosal and J. E. Berthold, “Robust Control of National Integrated High-Speed Network Infrastructure,” ATP Workshop on Networking, Telecommunications and Information Technology, Gaithersberg, MD, August 30-31, 1994.

Dipak Ghosal, “Performance, Fault-Tolerance and Network Control Issues in Database Management Schemes for PCS,” International Teletraffic Congress: Mini-seminar on Mobility and Intelligent Networks, Montebello, Canada, October 1994.

Dipak. Ghosal, Pietro Manzoni and Guiseppe Serazzi, “Performance Analysis of Different Approaches to Mobile Computing,” 6th IEEE Workshop On LAN And MAN, San Diego, California, USA, October 1993.

Dipak Ghosal and Pietro Manzoni, “Performance of a Network Layer Protocol Supporting Host Mobility in a Wide Area Network,” Second IEEE Workshop on the Architecture and Implementation of High Performance Communication Subsystems, Williamsburgh, VA, September 1-3, 1993.

L. Ney, M. Becker, S. K. Tripathi, W. T. Lo and Dipak Ghosal, “An experimental evaluation of a task allocation algorithm on hypercube architecture,” Proceedings of the Fifth International Conference on Computer Performance Evaluation Modelling Techniques and Tools, Edited by G. Balbo and G. Serazzi, Amsterdam, Netherlands: North-Holland, 1992, pp. 197-213.

Satish K. Tripathi, Dipak Ghosal and Guiseppe Serazzi, “Processor Scheduling in Multiprocessor Systems,” Invited Paper to First International Conference of the Austrian Center for Parallel Computation, Salzburg, Austria, 30 Sept.-2 Oct. 1991. Edited by: H. P. Zima. Berlin, Germany: Springer-Verlag, 1992., pp. 208-25.

Dipak Ghosal and Xiangdong Yu, “Optimal Dynamic Scheduling of Task Trees on Constant Dimensional Architectures,” 4th Annual ACM Symposium on Parallel Algorithms and Architectures, June 1992, San Diego, California, pp. 138-146.

Erol Gelenbe, Dipak Ghosal and Satish K. Tripathi, “Analysis of Processor Allocation in Large Multiprocessors,” Proceedings of the International Conference on the Performance of Distributed Systems and Integrated Communication Networks, Kyoto, Japan, September 1991.

Dipak Ghosal and A. R. Shah, “Trade-off between response and availability in distributed database system,” 14th ACM SIGOPS European Workshop on Operating Systems Principles, Bologna, Italy, September 1990.

Win-Tsung Lo, Dipak Ghosal and Satish K. Tripathi, “A Scheme for Allocating Task Graphs on Hypercubes,” European Symposium on High Performance Computing, France, March 1989.

Laxmi, N. Bhuyan, Hong Jiang and Dipak Ghosal, “From interconnection network to task level analysis,” Proceedings of the 1989 International Conference on Parallel Processing, Vol.1, St. Charles, IL, August 1989, pp. 73-77.

Dipak Ghosal, Laxmi N. Bhuyan, Hong Jiang and Satish K. Tripathi, “Analysis of Computation Communication Issues in Dynamic Dataflow Architectures,” Proceedings 16th Annual International Symposium on Computer Architecture, Jerusalem, Israel, May 1989, pp. 325-333.

Win-Tsung Lo, Dipak Ghosal and Satish K. Tripathi, “A Scheme for Allocating Task Graphs on Hypercubes,” European Symposium on High Performance Computing, France, March 1989.

Recent Colloquia, Talks and Tutorials

A Review of the Architecture and the Underlying Protocols in the Telephone Network, August 2003 Sprint Labs Burlingame, CA

Security Issues in IP Telephony, March 2003, Sprint Labs, Burlingame, CA

Teaching

Undergraduate Courses:

ECS 152A - Computer Networks: This course educates the student on the physical aspects of data transmission, on the protocols at the data-link level, on the seven-layer model (and the functions of the various layers) of the ISO Open System Interconnection Model, on transport and application level protocols, and on the principles in local area networks (LANs) and wide area networks (WANs). At the end of the course, students are able to understand the underlying principles in computer networks, and to develop network applications and interfaces with reasonable effort. They are also prepared to undertake an in-depth study of local and wide area networks dealing with their access mechanisms, performance evaluation methodologies, and related issues. Text book: William Stallings, Computer Networks, 5th Edition. Taught in Fall 1996, Winter 1998.

ECS 152B - Computer Networks: This course is a follow-on to ECS 152A. While ECS 152A deals with the fundamental principles of networking and concentrates on the lower layers of the protocol stack, ECS 152B is devoted to upper-layer protocols, in particular on the development of software that are used in computer networks. The course provides the required basics that are needed to develop networking software along with case studies of several networking applications. Students understand how to design and develop networking software and determine where improvements can be made by critically examining some existing applications. Through a number of assignments/projects, students gain hands-on experience by developing a number of simple network protocols and applications on an experimental Ethernet network in the Computer Science Department's Instructional Facility. Text books: 1) W. Richard Stevens, Unix Network Programming, 2) W. Richard Stevens, TCP/IP Illustrated Volume 1: Protocols. Taught in Spring 1996, Winter 1997, Winter 1998

Graduate Level Courses:

ECS 252: This is the core graduate level course in computer networks. The course educates the student on the principles in circuit and packet switched (wide area) networks as well as broadcast (local area and satellite) networks, on the principles of transport, network and data link layer protocols, on the design issues in computer networking applications. At the end of the course, students will be able to understand the underlying principles in computer networks, and to design and analyze network architectures. They will also be prepared to start research work in local and wide area networks dealing with their access mechanisms, routing algorithms, performance evaluation methodologies, and related issues. Students will gain experience in the design and analysis of network protocols through simulation and analytical models.

ECS 257: While ECS 252 is the core graduate course in computer networks and deals with the fundamental principles of networking, ECS 257 is devoted to mobile and wireless networks, in particular, on the protocols and architectures of existing and emerging wireless networks. The course will develop the fundamental concepts in wireless networks; the different access technologies, handoff control and mobility management protocols, and existing and emerging applications. Through assignments, and projects, the students will learn the key design issues in wireless networks supporting traditional voice applications as well as Personal Communication Services (PCS) and new multimedia applications. This course will prepare the students to start research in the area of the mobile and wireless networks.

ECS 256A: Analytical Techniques for Design and Analysis of Computer System. In this course we study analytical and simulation techniques to evaluate computer and communication systems. The analytical techniques are based on queueing theory and simulation technique is on discrete event simulation models. The course emphasize application of these techniques in real computer and communication system design. Teaching materiel: 1) Kishore S. Trivedi, Probability and Statistics, Reliability and Queueing Theory, and Computer Science Applications, and 2) recent published research papers. Taught in Winter 1997

ECS 256B: Analytical Techniques for Design and Analysis of Communication System. ECS 256B: Analytical Methods for Communication Systems Design The objective of this course offered in Spring 1997, was to get an in-depth understanding of the congestion control algorithms in the existing TCP/IP networks, in the telephone network, and the next generation high-speed networks based on ATM technology. The course covers the basic algorithms for congestion control in TCP/IP networks including slow-start, fast-retransmit, fast-recovery and congestion avoidance algorithms. The material is based on key research papers on congestion control algorithms in TCP and feedback control algorithms in ATM ABR and books that provide an in-depth discussion on various aspects of the TCP/IP protocol suite. A term project based on the network simulator (ns) developed in LBNL, is used as a means to identify and carry out design and analysis of a specific problem related to the TCP/IP protocol suite. Teaching material: 1) W. Richard Stevens, TCP/IP Illustrated, Volume 1 - Protocols and 2) recent published research papers. Taught in Spring 1997. This course will be significantly modified in subsequent offerings. It will cover more of the mathematical techniques that are required to analyze modern computer networks.

ECS 289: Special topics in Computer Networks. Research issues in the design of next generation wireless networks: cellular systems, medium access techniques, signaling, mobility management, control and management for mobile networks, wireless data networks, Internet mobility, quality-of-service for multimedia applications, caching for wireless web access, and adhoc networks.

Other

Taught an internal Bellcore course on performance evaluation of parallel architectures. Developed part of an ATM course for Bellcore Training and Education Center (TEC).

Student Advising/Mentoring

Jennifer Yick (PhD): Dissertation Topic: Sensor Networks.

Julee P. Pandya (PhD): Dissertation Topic: Caching Issues in Wireless Networks

Vijoy Pandey (PhD expected 2003) Dissertation Topic: Next Generation Wireless Networks.

Joey Anda (MS, 2005): Research Area: Vehicular Ad Hoc Networks.

Daniel Fernandez (MS, 2005): Research Area: Multimedia Distribution Using P2P

Howard Cheung (MS, 2004): Research Area: Vehicular Ad Hoc Networks.

Jeremy Abramson (MS 2003): Thesis Title: Next Generation Signaling Networks. Pursuing PhD at University of Southern California.

Archana Bharatidhasan (MS 2003): Thesis Title: Optimizing Placement of Services in a Sensor Network.

Vijay Ponduru (MS expected 2003): Thesis Title: Energy Aware Multipath Routing

Brennen Reynolds (MS 2002) Thesis Title: Security Architecture for IP Telephony.

Keith Kong (PhD 2002): Thesis Title: Pseudoserving: A Client-centric Paradigm for Service and Resource Exchange.

Xiaoxin Wu (PhD 2001): Thesis Title: Architectures for Next Generation Cellular Networks.

Ashok Swamy (MS): Thesis Title: Analysis of TCP over Satellite Links.

Sujatha Balaraman (MS 2001): Thesis Title: A Study of Pricing Policies in IP Telephony. Currently Employed at EFI

ArijitMukherji (MS 1999): Thesis title: “The Impact of Background Traffic on the Effectiveness of FEC for Packet Audio over Internet.” Currently employed with Cisco Systems.

Raja Mukhapadhaya (MS 1999): Thesis title: “A New Demand Driven Data Diffusion Algorithm for Hierarchical Caching.” Currently employed with Cisco Systems.

Todd Sinclair (Undergraduate) supported through NSF REU.

Angelina McCleod and Marilu Montero, MURPS 1998 summer undergraduate research program - supported by NSF.

Angelina McCleod and Theresa White, MURPPS 1997 summer undergraduate research program - supported by NSF.

Narana Kannappan (MS 1997): Thesis Title “A Study of the Interaction Between TCP and ABR ATM Flow Control Mechanisms.” Currently employed with Cisco Systems.

Grants and Awards

1997: UC Davis Information Technology Equipment Grant. PI: Dipak Ghosal.

1997-1998: UC Davis: Junior Faculty Research Fellowship. PI: Dipak Ghosal

1997-1998: UC Davis Faculty Research Grant. PI: Dipak Ghosal

1998-1999: MICRO Grant. Title “Emerging Customer Data Network Management.” (Industry support committed from SBC). PIs: Biswanath Mukherjee and Dipak Ghosal.

1997-2002: NSF Career Award. Proposal Title “A Career Development Plan for Research and Education in High Speed Networks.” PI: Dipak Ghosal

1998-2003: NSF Award. Proposal Title “Complementing Internet Caching with Pseudo-serving to Mitigate Network Congestion.” PIs: Dipak Ghosal and Louis S Hakimi

2002-2003: HP Technology Award, Mobile Technology Solutions Grant, Pis: Prasant Mohapatra and Dipak Ghosal

2003–2004: Sandia Labs. Title “Application of Mobile Ad Hoc and Sensor Networks for Facilities Protection,” PI: Dipak Ghosal.

2003– 2004: Los Almos National Labs. Title: Wide-Area Transport and Signaling Protocols for Genome To Life (GTL) Applications. PIs: Biswanath Mukherjee, Dipak Ghosal and Wu-Fung Chung

2003– 2005 NSF Award: Proposal Title: Security Architecture for IP Telephony. PIs: Dipak Ghosal and S. Felix Wu.

2003–2004: California Institute for Energy Efficiency (CIEE). Proposal Title: Enabling Demand Response with Vehicular Mesh Networks (VMesh). Status (pending): PIs: Chen-Nee Chuah, Dipak Ghosal, and Michael H. Zhang.

2003–2005: NSF/DOT: Proposal Title: Enhancing Mobile Target Detection Using Vehicular Ad Hoc Networks. Status Pending. PIs: Dipak Ghosal and Michael H. Zhang

Patents/Inventions

Keith Kong and Dipak Ghosal, “A Self-Scaling Scheme for Avoiding Server-Side Congestion in the Internet,” Approved October 2002, US Patent 6,473,401 B1

Recent University and Department Service

2001-2003: College of Engineering Student Development Committee

2001-2003: Faculty Recruitment Committee

2000-2001: Graduate Admissions Committee

1997-1998: Departmental representative to MURPPS (Minority Undergraduate Research Program in Mathematical and Physical Sciences).

1996-1998: Campus technical committee on the deployment of the new ATM-based campus backbone network.

1997-1998: Member of the Graduate Admissions Committee (Computer Science Department).

1996-1998: Member of the Departmental Committee on Information Technology (Computer Science Department).

1996-1997: Member of the Departmental Committee on Industrial Affiliates Program (Computer Science Department).

1997-1998: Member of Departmental Committee on Educational Outreach (Computer Science Department).

1997-1998: Member of Departmental Committee on Public Relation (Computer Science Department).

1997-1998: Member of the Faculty Recruitment Committee (Electrical and Computer Engineering Department).

Professional Activities

Member of NSF Panel – Special Projects in the ANIR Program

Referee for NSF Proposals

Referee for IEEE Transactions on Networking

Program Committee Member of 1995, 1996, 1997, 1998, and 1999 INFOCOM

Program Committee Member of 1995, 1996 Distributed Computing Conference

Program Committee Member of MASCOT 1994

Referee for IEEE Journal of Selected Areas in Communication

Referee for IEEE Transactions on Computers

Referee for IEEE Computer Magazine

Referee for Journal of Parallel and Distributed Computing

Referee for IEEE Transactions on Software Engineering

Member of IEEE Computer Society

Member of IEEE Communications Society

Other Interests

Travelling, teaching, cooking, tennis, and social activities concerning children.

Current Research Projects

IP Telephony

There is tremendous interest in IP Telephony solutions by businesses of all shapes and sizes. IP Telephony offers many advantages over the regular Public Switched Telephone Network (PSTN), including new advanced services, lower costs, efficient resource utilization, and ease of management through consolidation of network resources. Despite these benefits and rapid advances in development of standard protocols and interfaces for IP Telephony, there remain significant challenges in supporting toll quality voice over a converged PSTN and IP network. These challenges stem from the inherent differences between the PSTN and the IP network. The latter is still primarily a best effort network and hence, unlike the PSTN, provides no guarantees on the Quality of Service (QoS).

A key objective of this proposed project is to support dynamic and adaptive deployment of IP Telephony services and network resources. This will be accomplished through a resource management architecture that can support several different levels of IP Telephony service each with different QoS guarantees for voice traffic over a converged PSTN and a best effort IP network. The goal is to design a set of resource management algorithms that can maximize networkresource utilization, maximize economic efficiency (i.e., users who are willing to pay more are preferentially allocated higher quality resources ahead of other users under overload conditions), and maximize revenue. We will investigate the following specific questions in this proposed research: What is an effective calladmission control algorithm for IP Telephony? What are the building blocks for implementing a good resource reservation algorithms in a dynamic distributed network? What is a robust algorithm for routing a call in a multilayer (converged) network with different cost structures and QoS support in each layer? What are good algorithms for balancing traffic across gateways that interconnect the PSTN and the IP network? We will build upon preliminary research work on a dynamic pricing based call admission control algorithm and a gateway selection algorithm that supports call redirection based on both gateway congestion and path QoS in theIP network.

Another important goal of this proposed research is to define a security architecture to allow IP Telephony to inter-operate with network middle-boxes such as network address translators and firewalls while retaining good security. A key objective of the security architecture will be to detect and counter new types of network vulnerabilities. Additionally, we will architect a measurement, monitoring, and control infrastructure for IP Telephony networks. The goal of this infrastructure is two-fold. First, this infrastructure will provide the measurements that will be required to support the differentiated service architecture. These measurements will include network characteristics such as path quality to different gateways and gateway resource utilization. Second, the infrastructure will also provide support for the security architecture. We will investigate the following key questions in this work: What are appropriate techniques for measuring path and node characteristics? What are effective end-to-end control algorithms to mitigate overload conditions in the converged network? What are the building blocks of a scalable security architecture for IP Telephony? What are new network vulnerabilities associated with IP Telephony and what are the appropriate counter measures? We will build upon preliminary research on automatic detection and control of focussed overload conditions in the PSTN and preliminary work on defining a framework for supporting secure IP Telephony over network middle-boxes.

IP Telephony is a strategic Internet technology. Resolving the issues described in this proposed research will determine the pace with which IP Telephony is adopted both in the enterprise and in the mainstream consumer markets. The proposed research will build upon successful preliminary research work and also leverage significant past experience of the PI in traditional telephony networks, protocols and algorithms.

Peer-to-Peer Networks

Much has evolved in the peer-to-peer (P2P) space since our original work on pseudoserving in 1997 [1] [2] . Napster and Gnutella have popularized the space, and inspired many projects in academia and in industry. Work is now underway to develop industrial-strength systems by applying results from more developed areas of research, including coding theory and distributed systems. As part of this maturation process, various groups are proposing to develop P2P middleware. Their goal is to factor out common functionalities from various projects, implement them in a robust manner, and make them available to application programmers through well-defined interfaces. We believe these efforts will spawn a new era of growth in the P2P space by making accessible to the application programmer a powerful, but highly complex technology.

While current proposals for a P2P middleware provide many services useful to application programmers, they do not capture a crucial aspect of P2P systems: that of providing incentives for users to contribute their resources to the system. Without such incentives, empirical data show a majority of the participants act as free riders who do not contribute resource. As a result, a substantial amount of resource goes untapped, and, frequently, P2P systems devolve into client/server system with attendant issues of performance under high load.

We propose to address the free rider problem by introducing the notion of a P2P contract. In it, peers are made aware of the benefits they receive from the system as a function of their contributions. Such a system rewards users who contribute resources. At the same time, it allows free riders so long as they do not unduly impact the quality of service for others. This proposal focuses on three objectives:

1. Modeling the economics of P2P systems. This effort provides a framework upon which P2P contracts can be constructed. Utilities that users derive from a service are modeled as functions of service attributes. Service attributes, in turn, are modeled as functions of resource allocations. By using these models, one can determine the set of resource contributions that satisfies both the goal of the system and the goal of the user. A resource contribution within this set and the service level corresponding to that contribution constitute the terms of the P2P contract.

2. Developing resource allocation methods. This effort serves to make tractable the computations that result in the terms of P2P contracts. Various strategies are considered, including parameter consolidation, quantization, and dynamic programming. A novel aspect of this work is the implementation of these strategies in a form suitable for computation by the P2P system.

3. Developing a middleware-based P2P system incorporating contract mechanisms. This effort serves to demonstrate the value of optimizing for utility in a P2P environment, to provide a framework for testing models and algorithms for resource allocation based on the utility of services to users, and to provide direct experience in integrating the contract mechanism in middleware.

Resource Management for End-to-End QoS in Integrated Mobile Networks:

We propose to study distributed real-time resource management in an integrated wireline/wireless network infrastructure that can support multiple user classes and applications with varying Quality of Service (QoS) requirements. This project focuses on three specific areas of research: (1) channel allocation in multi-tier cellular networks, (2) protocols and algorithms for distributed mobility management, and (3) a software toolkit to investigate the cumulative impact of the protocols and algorithms developed in parts (1) and (2) on the QoS of different applications. The primary issues, the key innovations, and the expected impact of each of these research topics are summarized below:

Channel Allocation in Multi-tier Cellular Networks: In a multi-tier cellular network, macrocells with a larger coverage area are overlayed over microcells with smaller coverage area. Such a network architecture, if properly engineered, can provide improved QoS over the traditional single-tier cellular network under the same resource constraints, viz., a limited set of available frequency channels. The multi-tier network can provide greater flexibility in supporting multiple user classes and applications. We propose to develop algorithms for static and dynamic allocation of channels among the multiple tiers to meet the QoS requirement of various applications for different user mobility classes. The expected outcome of this effort include new algorithms to allocate users to appropriate tiers, application of external vehicular traffic information systems in dynamic channel allocation strategies, and new mathematical techniques and improved approximations to solve the associated system models.

Protocols and Algorithms for Distributed Mobility Management: Mobility management defines functions that are required to support various types mobility such as user, terminal, service, and network mobility. In this research, we will develop protocols and algorithms to implement mobility management functions in a distributed manner in order to support diverse classes of mobile users in a highly dense and highly mobile environment. The key innovations in this research will be novel data replication and load balancing strategies so that the mobility management functions meet the specified performance and fault-tolerance guarantees. This research will lead to insights on the applicability of distributed computing algorithms for mobility management in an integrated wireline/wireless network.

An Engineering Toolkit to Study Resource Management Algorithms: We will develop a software tool which can be used to study the impact of various resource management algorithms on the end-to-end QoS of different applications. The toolkit will include tools to model the network, implement various distributed mobility management schemes, model the multi-tier cellular network and the associated channel allocation algorithms, and incorporate various models for user mobility and traffic classes. The toolkit will help us understand the impact of channel allocation and mobility management algorithms on call processing and signaling network overheads.

The overall goal of this research is develop protocols and algorithms for resource management in next-generation integrated networks. In this research, we will integrate research results in mobility management, distributed computing algorithms, user mobility and traffic models, and multi-tier cellular networks in a common framework to investigate their impact on the QoS of different applications.