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University: University of Victoria Name of Sponsoring Professor: Dr. Aaron Gulliver Department: Electrical and Computer Engineering We are using OPNET to perform an extensive simulation study was done to gauge the performance of parallel access to multiple mirror sites on the Internet. The study is based on the Digital Fountain approach designed by J. Byers et al. Tornado codes were used to minimize decoding time with the expense of injecting extra packets into the system to establish a successful decoding. In our study, both Reed-Solomon codes and Tornado codes were considered. Moreover, our results indicate that randomly permuting the packets at every mirror server is not the optimal solution. A new technique, which staggers the packets, has shown to have superior behavior. Our study used OPNET Modeler, being a powerful event driven simulation tool. The model mimics the environment of multiple mirroring efficiently, we have created several scenarios to demonstrate accurate comparison modes for random permutations, staggered and enhanced staggering modes. OPNET is one of the most powerful Graphic User Interface (GUI) network simulation tools. It is based on the concept of event driven simulation, which allows a very close look at the performance of the system under investigation. The software embedded within OPNET provides precise probing of system parameters. OPNET provides a comprehensive development environment supporting the modeling of communication networks and distributed systems. Both behavior and performance of modeled systems can be analyzed by performing discrete event simulations. Simulation showed that using both staggered and enhanced staggered packet transmission techniques with Reed-Solomon codes can dramatically improve system speedup and overall reception efficiency. The procedure proved robustness in the face of high packet loss ratios at very low stretch factors (high code rates), which are highly desirable. Publications: Y. Abdel-Hamid and T.A. Gulliver, “Parallel Access to Multiple Internet Mirror Sites. A Performance Study”, IEEE Pacrim, Victoria, BC. Canada, pp. 816-819, August 2003 Y. S. Abdel-Hamid and T.A. Gulliver. “Improved Access to Multiple Internet Mirror Servers”, The 46^th IEEE International Midwest Symp. on Circuits and Systems. Cairo, Egypt, Dec. 2003 (submitted)