My early research was exclusively in global performance and resource optimization for optical networks, and I continue to have research interest in various optical networking issues, such as converter placement, traffic grooming, survivability, slack assignment and other areas in resource allocation More recently, I am also involved in Internet architecture research, wireless and mobile network design, and research infrastructure design - all crucial areas in networking that are gathering increasing attention from the research as well as practitioner communities.
Another important thread is the issue of network and service continuity - the fault tolerance of networks, and the continued predictable and dependable performance, when conditions depart from the nominal. Such departures may be caused by malicious action by an adversary, requiring network security measures, or be caused naturally, which also requires pre-planning and appropriate design to provide continuity.
The unifying theme in these activities, to my mind, is to achieve increasingly tight coupling of the network to "real" information: information from applications, from other computing entities, from the physical world beyond computing. As solutions to traditional networking challenges become more commoditized, these are the areas the new networking challenges will come from.
The links above provide information on my research students, current and past research projects, publications; there is a brief overview (a personal view) of research which I hope helps you if you are considering getting into academic research, as well as specific information regarding working with me on your research. Other than describing active or past research projects, I also provide a section on areas of potential research, which range from well-considered roadmaps to vague ramblings.
Here are some links to current stuff: more details in the "Projects" section.