Title: Traffic Scheduling and Multicasting in Broadcast WDM Networks

Abstract:

The talk will consider the problem of scheduling packet transmissions
 in a broadcast wavelength division multiplexing (WDM) network with
 non-negligible transceiver tuning latencies. 
The scheduling problem is formulated as a generalization of the
 classical open-shop scheduling problem.
We will present a special class of schedules and a new algorithm for
 open-shop scheduling; the algorithm will be shown to be optimal when
 the traffic demands satisfy certain conditions.
We will then describe heuristics which exhibit good average case
 behavior under arbitrary traffic demands.

We will extend the problem formulation to include multicast traffic.
We will first show that bandwidth consumption and channel utilization
 arise as two conflicting objectives in the design of algorithms in
 this environment.
We will then present a new technique for transmitting multicast
 packets, based on the concept of virtual receivers.
Our approach decouples the problem of determining the virtual receivers
 from the scheduling problem, making it possible to employ the
 scheduling algorithms developed for unicast traffic.
Finally, we will present four heuristics of varying degrees of
 complexity that provide a good balance between the two conflicting
 objectives.

Short Bio:

George Rouskas received his MS and PhD degrees in Computer Science from
 Georgia Tech in 1991 and 1994, respectively.
He is currently an Assistant Professor in the Department of Computer
 Science at North Carolina State University, where he has been since
 1994.
He is the recipient of a 1997 NSF Faculty Early Career Development
 (CAREER) Award, the Department of Computer Science 1995 Outstanding
 New Teacher Award, and the 1994 College of Computing Outstanding
 Research Assistant Award.