COMPASS: Composable and Parallel Simulation of Internetworks

互联网前所未有的指数级增长已经远远超出了分析现代网络所需工具的能力。 仿真仍然是网络设计人员、研究人员和管理人员解决许多分析问题的首选方法。 然而，现代仿真工具通常仅限于分析数十到数百个网络节点，而对当前和未来网络（如下一代互联网）的研究需要分析数千万个节点。 新的，实用的网络建模和仿真方法需要解决这个日益严重的问题。 当今仿真技术中经常听到的两个问题是：（1）为一个大型网络建立模型所需的时间过长;（2）执行仿真程序所需的计算机时间过长。 这个项目，称为COMPASS（COMPOSable and PARCHEMICAL SIMULATION of internetworkS），将通过定义和实现一种方法来解决第一个问题，该方法通过重用其他人开发的模型组件，可能使用不同的仿真软件包来快速构建网络模型。 第二个问题将通过在并行和/或分布式计算机上执行模型来解决。 在这方面，本项目将重点实现一个实用的，灵活的，并行化的方法，可以被广泛利用的网络community.This方法，基于组成（联邦）自主的模拟器上执行differentprocessors，干净地分离的并行和顺序部分的模拟，允许并发优化和细化的每一个。 一个相关的问题，将被研究concernsexecution的模型在地理上分布的区域的情况下，模型组件不能很容易地协同定位。 为了演示这种方法，ns2simulator的优化并行/分布式实现将作为本项目的一部分实现。 该软件将在广泛可用的计算平台上实现，并将与南加州大学/ISI的VINT/ns小组一起免费提供给网络社区。 由于ns2在网络社区中被广泛使用，因此该项目的潜在影响很大。此外，能够很容易地重用其他人使用不同的仿真软件包开发的网络模型，可以导致一个范式转变的方式建模和仿真是例行实践中的网络community.Finally，多播协议的仿真将被用来作为一种工具，以评估和完善并行仿真设计，并证明其有效性。 组播协议对可扩展的仿真工具的需求尤为强烈。 这是一个仍在产生新的想法和建议的领域。 本计画的研究将集中于目前网际网路社群所感兴趣的多播协定，包括可靠多播、分层视讯多播及资料散布应用。 这项工作不仅为并行仿真研究提供了概念证明，而且还为网络社区提供了改进的评估能力，以解决当前感兴趣的问题。

The unprecedented, exponential growth of the Internet has far outstripped the capacity of thetools needed to analyze modern networks. Simulation remains the method of choice for networkdesigners, researchers, and managers for many analysis problems. However, modern simulationtools are typically limited to analyzing tens to hundreds of network nodes, while studies ofcurrent and future networks such as the next generation Internet call for analyses of thousands tomillions. New, practical approaches to network modeling and simulation are needed to addressthis growing problem. Two frequently heard problems with simulation technology today are (1) the excessive amountof time required to construct a model for a large network, and (2) the inordinate amount ofcomputer time required to execute the resulting simulation program. This project, calledCOMPASS (COMposable and PArallel Simulation of internetworkS), will attack the firstproblem by defining and realizing an approach to enable rapid construction of network modelsby reusing model components developed by others, possibly using different simulation softwarepackages. The second problem will be attacked through execution of the model on paralleland/or distributed computers. In this regard, this project will focus on realizing a practical,flexible, approach to parallelization that can be widely exploited by the networking community.This approach, based on composing (federating) autonomous simulators executing on differentprocessors, cleanly separates the parallel and sequential portions of the simulation, allowingconcurrent optimization and refinement of each. A related problem that will be studied concernsexecution of models over a geographically distributed area in situations where modelcomponents cannot be easily co-located. To demonstrate this approach, an optimized parallel/distributed implementation of the ns2simulator will be realized as part of this project. This software will be realized on widelyavailable computing platforms and will be made freely available to the networking community incollaboration with the VINT/ns group at USC/ISI. Because ns2 is widely used in the networkingcommunity, the potential impact of this project is large. Moreover, the ability to easily reusenetwork models developed by others using different simulation packages can lead to a paradigmshift in the way modeling and simulation is routinely practiced in the networking community.Finally, simulation of multicast protocols will be used as a vehicle to evaluate and refine theparallel simulation designs and demonstrate their effectiveness. Multicast protocols have aparticularly strong need for scalable simulation tools. It is an area where new ideas andproposals are still being generated. Research in this project will focus on multicast protocols thatare of current interest to the Internet community; reliable multicast, layered video multicast anddata dissemination applications will be studied. This work will not only provide a proof ofconcept for the parallel simulation research, but will also provide an improved evaluationcapability to the networking community for solutions to problems of current interest.