My research is in the area of computer/telecommunication networks on the topics of network design, development and evaluation of network controls, performance modeling techniques and more recently in the area of security. The research for which I am probably best known is network design and traffic restoration, where I have focused on both wired and wireless networks with a particular emphasis on techniques for designing networks which are survivable to failures and attacks. This work has been within various network technological settings ranging from ATM to 3G wireless to most recently Overlay- IP-WDM networks. My research in this area has been supported by grants for IBM, NSF, DARPA, and NIST as well as several consulting projects. For example, in a series of conference (Globecom, Infocom, DRCN) and journal papers (e.g., ACM/IEEE Trans. on Networking 2005, IEEE JSAC 2007) we developed a novel approach to the near optimal real time provisioning of survivable virtual network topologies over a core network was developed. A patent was granted on this work in 2004. I am continuing to work in this area and have broadened the scope to include the interaction of survivability and security, which have been the focus of recent grants from NSF. Related to this work, I have co-edited and co-authored a book on information assurance looking at how security and dependability are intertwined. A listed of papers I have published in this area are listed here.
In the area of network control, I have worked on the development and performance evaluation of routing algorithms, buffer management, bandwidth allocation, queue scheduling, overload/flow control and call admission/access control. These problems have been studied in the context of different network technologies such as multi-rate circuit switched networks, frame relay service, and high speed packet switched networks such as ATM and MPLS/IP and more recently wireless networks (3G, sensors, ad hoc, etc.). I have been particularly interested in the development of network controls which adapt to changing network conditions in a manner that improves network performance and the design of controls to support a required quality of service. I have published a number of papers in this research area which are listed here and have chaired or co-chaired four doctoral dissertations related to this topic.
In the area of performance modeling techniques, I have worked on developing a set of methods/algorithms for studying the time varying behavior of queueing systems either via analytical models or simulation. This work originated in my doctoral dissertation and has been extended in a number of student theses. Much of my work on network survivability and some of the models used in network control work are an application of these theoretical approaches to a specific problem. I have had funding for this work while at Pitt from MCI and a grant from IBM while at Clemson. Recently I have been working on developing performance techniques for modeling ad hoc networks. Publications related to this area are listed here.