Differentiated Services Support for the Helios Optical Access Network Testbed

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Title: Differentiated Services Support for the Helios Optical Access Network Testbed
Author: Bengeri, Sudhindra Suresh
Advisors: Dr. George Rouskas, Chair
Dr. Harry Perros, Member
Dr. Robert Fornaro, Member
Abstract: We consider the problem of scheduling a differentiated mix of (IP DiffServtype) traffic in a broadcast single hop WDM network. Tunability isprovided only at one end, namely at the transmitter. Our objective is todesign transmission schedules to schedule a mix of guaranteed service andbest-effort traffic, by allocating the excess bandwidth to best-efforttraffic in a manner. We consider scheduling algorithms forboth systems with negligible transceiver tuning latency and systems withnon-negligible transceiver tuning latency. We map the optimal preemptive scheduling algorithm to schedule packets in a system withnegligible transceiver tuning latency and use the nonpreemtive scheduling algorithm for systems with non-negligible transceiver tuninglatency. We propose mechanisms for the allocation of slots to best efforttraffic for the preemptive and non-preemptive scheduling algorithms. Wepresent the results of extensive simulation study that evaluate theperformance of the best effort allocation schemes in terms of channel throughput and schedule lengths. We identify the effect of schedulelengths and percentage reservations for guaranteed traffic on schedulingdelay, and develop heuristics that effectively decouple the effect ofschedule lengths on scheduling delay. We then present the architecture ofthe highly extensible WDM simulator component we implemented over .The component can be used to study the performance of collision-freescheduling algorithms and queuing mechanisms on a TT-FR broadcast singlehop WDM network. Finally, we use this simulator component to study theeffects of different system parameters, such as slot demands andreservations on scheduling delay, and delay jitter.
Date: 2001-07-19
Degree: MS
Discipline: Computer Science
URI: http://www.lib.ncsu.edu/resolver/1840.16/2852


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