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Presentation Slides for Recent Papers

Research Interests and Areas

My primary research interest is in optical networks, at the networking layer. The development of dWDM (allowing many channels of communication over the same fiber) and wavelength routing (allowing fast switching at the optical layer), coupled with the huge increment in available bandwidth that the use of fiber allows, has changed the way we look at some networking problems, as well as given rise to new ones. My interest is currently in two major areas, that of traffic grooming and fault tolerance. I have a secondary interest in performance and management of optical networks, as well as ad-hoc networking. under construction

Traffic Grooming

The quantum jump in transmission speed due to the use of fiber has not been accompanied by a similar improvement in processing speed at intermediate network processing elements (routers, switches). As a consequence, either the fiber has to be severely underutilized (not a preferable solution, and not viable in the long run), or many processing elements have to be deployed to conventionally route/switch at each intermediate (network interior) node. This latter solution can be prohibitively expensive. In addition, the processing equipment is all electronic, thus delay is incurred in electro-optic conversion every time the packets/cells contained in an optical signal must be routed. This will usually be necessary because the bandwidth of even a single wavelength is likely to be much larger than the typcial user channel bandwidth, thus many slower speed traffic streams will be multiplexed (probably TDM) over each wavelength channel. It becomes very attractive to allow some (hopefully the bulk) of the traffic to be switched optically, using wavelength routing, and resort to electro-optic conversion and electronic processing only when it cannot be avoided. This problem has been called traffic grooming in literature. In the general case, as well as in many quite restrictive cases of topology and traffic patterns, this problem is computationally intractable. My research concentrates on finding theoretical results characterizing optimal solutions to different traffic grooming problems and relations between them, as well as the development of heuristic solutions. See the technical report linked below for a thorough overview and review.

Protection and Restoration

As tomorrow's networks grow in speed and reliability, they are going to take over many functions for which computer networking is not currently the primary or preferred vehicle. This is going to result in tomorrow's optical backbone acquiring a "lifeline" characteristic which it does not have now. Reliability and fault tolerance are going to be important issues in such a network. The protection and restoration research area addresses these issues. Usually, we make a distinction between proactive (plan beforehand for a link or node failure) or reactive (once a failure occurs, respond, taking network state into account) approaches. Approaches can focus purely on the optical layer or involve co-operation between the optical layer and its client layer (such as IP). Research areas address design optimization for static as well as dynamic (blocking characteristics) considerations. under construction

Technical Reports

The following technical reports are available from the Computer Science departmental Technical Report Archive. See the resume section for refereed publications.

Prospective Research Students

If you are considering research work with me, thank you for your interest in my research. These are some of the points to consider with respect to possible research work with me:

Students sometimes ask me about independent studies: while basically it is a good idea, I cannot undertake to guide you in one at this time. I also encourage you to do most of the work for an independent study before the semester you actually register for it; this proves intent and reduces the chance that you may not get a satisfactory grade for it.

I wish you luck in your research endeavours, whether with myself or other faculty members.