WDM Networks can be Nonblocking without Wavelength Interchange

Richard Thompson (Pitt/Telecom)

Tuesday, April 17th, 2007
12 pm - SENSQ 5317

Refreshments at 11:45 am

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Abstract

Some papers in the literature claim to minimize the number of wavelength interchangers in a WDM network; others claim that wavelength interchange is NEVER needed (the minimum number is ZERO). It turns out that both are correct, depending on whether the underlying network topology has "sufficient spatial diversity." This talk has three parts, the first two of which correspond to two recently submitted papers.

Part 1 illustrates the tedious nature of research. It shows a set of elementary network topologies and the result of tediously analyzing the blocking characteristics of each one. Beside being interesting, informative, and entertaining, these results provided the insight for the second part.

Part 2 illustrates the importance of history in research. It presents the conditions for that "sufficient spatial diversity" that allows us to avoid interchanging wavelengths. These two conditions derive from a network transformation, which is based on a similar transformation from 35 years ago.

Part 3 illustrates that research never ends. It shows that a problem, which has remained unsolved for many years, now has even greater importance to be solved. I will show how I am trying to solve it (based on tedium and history).

Biography of Speaker

Dr. Richard A. Thompson has been a Professor of Telecommunications at the University of Pittsburgh since 1989, after 20 years at Bell Labs. He is the Chair of Pitt's Telecom Program, has a secondary appointment in Pitt's EE Department, and is affiliated with Pitt's undergraduate Photonics Program. His BS and MS degrees, each in EE, are from Lafayette College and Columbia, respectively. His PhD, in Computer Science, is from the University of Connecticut, where his major advisor was Taylor Booth. Besides peripheral research interests in human-computer interaction and in the statistics of packet dependence, Dr. Thompson's principal research area is Communications Switching, especially photonic switching and Voice over IP. Dr. Thompson was chair of the IEEE Comsoc Technical Committee on Switching and Routing. He is the author of "Telephone Switching Systems", principal co-author of "The Physical Layer of Communications Systems", and has over 80 research publications, mostly in IEEE journals and conferences.