A Generic Optimized Time Management Algorithms (OTMA) Framework for Simulating Large-Scale Overlay Networks

This thesis is being archived as a Digitized Shelf Copy for campus access to current students and staff only. We currently cannot provide this open access without the author's permission. If you are the author of this work and desire to provide it open access or wish access removed, please contact the Wahlstrom Library to discuss permission.Recent evolutions in wireless networks will require more efficient use of the underlying parallel discrete-event simulation (PDES) synchronization protocols to accommodate the demand for large-scale network simulation. In this dissertation, we investigate underlying synchronization protocols to improve the performance of large-scale network simulators operating over PDES systems. We begin by proposing a generic optimized time management algorithms (OTMA) framework that combines the improved forms of synchronization protocols on a single platform. Particularly, for the proposed OTMA framework, we use the layered architecture approach to combine the optimized forms of conservative and optimistic time management algorithms. To support the implementation of the OTMA framework, a new m -LP (logical process) simulation model is proposed. One of the other challenges of large-scale network simulations is the lack of a realistic analytical and mathematical model for underlying PDES protocols. In this research work, the proposed OTMA framework integrates both conservative and optimistic synchronization algorithms on a single platform. In particular, for the purposes of this research, we provide an improved form of NMA by developing a new deterministic model that quantifies the performance dependent critical parameters for PDES systems. In addition, for the implementation of NMA, a new m -LP simulation model along with the varying parameters network topology is proposed. Finally, we provide a quantitative model to support the simulation results and experimental verifications for NMA. The current DES based simulators have a large end-to-end latency and poor memory utilization. OTMA framework will provide an improved form of the existing Time Wrap algorithm by proposing a new unacknowledged message list (UML) scheme. The proposed UML scheme will provide global synchronization among large number of nodes along with a fool proof solution for message transient and simultaneous reporting problems. To illustrate the implementation of the proposed UML scheme, two algorithms are proposed for coordinating and non-coordinating LPs. In order to further improve the global virtual time (GVT) computation process, synchronous barriers (such as tree and butterfly barriers) will be combined with the asynchronous algorithms (such as Time Wrap algorithm) to provide an efficient GVT computation mechanism for large-scale distributed networks