Rapid growth in wireless communication systems motivates the development of technology supporting the simulation of large-scale wireless systems. However, it is widely recognized that wireless communications do not ha...
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ISBN:
(纸本)9780769516080
Rapid growth in wireless communication systems motivates the development of technology supporting the simulation of large-scale wireless systems. However, it is widely recognized that wireless communications do not have substantial "lookahead" needed by conservative synchronization protocols. This paper focuses on identifying and exploiting lookahead for such models. We find lookahead in three ways, exploiting characteristics of low power networks, the transceiver logic, and the way in which protocol stacks are typically constructed. We show how these observations allow a variety of conservative synchronization protocols to take advantage of lookahead, describe a synchronization method we use, and empirically examine the performance this method offers on a large-scale simulation of a sensor network intended for homeland defense scenarios
We describe a novel approach to scalability and efficiency of parallel network simulation that partitions the networks into domains and simulation time into intervals. Each domain is simulated independently of and con...
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ISBN:
(纸本)9780769516080
We describe a novel approach to scalability and efficiency of parallel network simulation that partitions the networks into domains and simulation time into intervals. Each domain is simulated independently of and concurrently with the others over the same simulation time interval. At the end of each interval, packet delays and drop rates for each inter-domain flow are exchanged between domain simulators. The simulators iterate over the same time interval until the exchanged information converges to a constant value within the prescribed precision. After convergence, all the domain simulators progress to the next time interval. This approach allows the parallelization with infrequent *** biggest challenge for this method is to ensure iteration convergence for protocols, such as TCP, that adjust source rate to the current network conditions. The main contribution of this paper is to demonstrate that by judicious design of the domain processing and information exchange, the proposed approach efficiently parallelizes network simulation with TCP flows.
This paper presents two new versions of the Critical Channel Traversing (CCT) algorithm. CCT is a conservative parallel discrete event simulation algorithm that has been shown to achieve very high performance when use...
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ISBN:
(纸本)9780769516080
This paper presents two new versions of the Critical Channel Traversing (CCT) algorithm. CCT is a conservative parallel discrete event simulation algorithm that has been shown to achieve very high performance when used in a wide area computer network simulator. The first of the new algorithms called simple sender side CCT is similar to the original, but busy waiting is eliminated. Results presented show that simple sender side CCT avoids performance problems that can be caused by busy *** second new algorithm called receive side CCT employs a different strategy for updating channel clocks and determining which objects should be scheduled on critical channels. Performance results show that this version provides better scaling with respect to the connectivity of the model, at the expense of some added complexity.
We present a case study in which we apply parallelsimulation methods and interoperability techniques to network simulations for simulation-based on-line control of military communication networks. The on-line simulat...
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ISBN:
(纸本)9780769516080
We present a case study in which we apply parallelsimulation methods and interoperability techniques to network simulations for simulation-based on-line control of military communication networks. The on-line simulations model actual military networks, including wired shipboard sub-networks connected via satellite links, and wireless mobile devices. The modeled scenario depicts the communication requirements of an amphibious landing where a complex network connects troops ashore and naval vessels. The simulations use a heterogeneous set of tools, including ns2 models for shipboard wired networks, and GloMoSim models for the wireless devices. In this paper, we document the challenges we encountered in applying parallel and interoperable simulation methods, and describe our solutions. We describe our experiences in addressing the interoperability problems that naturally arose due to the heterogeneity of scenario models. We also present a preliminary study on the scalability of real-time performance of parallel network simulations, which is crucial for on-line simulations. Salient system characteristics of the subject military network scenarios are described for the benefit of exposure to the modeling and simulation research community. Our exercise not only highlights the relevance of parallel and distributedsimulation techniques to an important real-life problem, but also demonstrates the feasibility of applying those techniques in a practical setting.
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