CRI: CRD: iSim - Simulator of Internet-Scale Events

蠕虫传播、分布式拒绝服务攻击、Flash群集、路由不稳定性和DNS攻击等Internet级事件的动态取决于生成或转发合法和恶意流量的所有网络的配置。为了充分理解这些事件，研究人员需要模拟工具，再现所有相关的事件细节和事件流量？与互联网架构的互动。针对互联网规模攻击的协作防御也已被提出。这些防御的有效性取决于底层的互联网拓扑结构和部署位置，因此高保真的互联网仿真是必要的，以正确评估这些防御。目前的网络模拟器不能用于研究互联网规模的事件。它们是通用的数据包级模拟器，再现了太多的网络通信细节，这限制了可扩展性。即使是为大规模事件设计的分布式网络模拟器，如GTNetS和PDNS，也具有有限的可扩展性，因为每个数据包及其处理都是详细模拟的。例如，PDNS需要强大的100多个CPU集群，以模拟多达1.28 M易受攻击主机的蠕虫传播。许多研究人员无法访问如此大的集群。当前网络模拟器的另一个缺点是它们缺乏内置的互联网模型。旨在模拟互联网规模事件的研究人员必须自己组装互联网拓扑结构，并确定终端主机通信模式，链路带宽和路由。从头开始建立一个现实的互联网模型所需的努力是相当大的，所以许多研究人员采用简化的模型（例如，假设无限带宽链路，假设高度对称的互联网拓扑等）这导致不正确的结果。iSim的工作建立在我们最近的成就，在创建一个互联网规模的蠕虫传播事件模拟器，称为PAWS。PAWS是一个分布式模拟器，部署在Emulab测试平台上。该项目将探索PAWS模拟器作为社区资源的潜力。

Dynamics of Internet-scale events such as worm propagation, distributed denial-of-service attacks, flash crowds, routing instabilities, and DNS attacks depend on the configuration of all the networks that generate or forward legitimate and malicious traffic. To fully understand these events researchers need simulation tools that reproduce all the relevant event details and event traffic?s interaction with the Internet architecture. Collaborative defenses against Internet-scale attacks have also been proposed. The effectiveness of these defenses depends on the underlying Internet topology and the deployment locations, so high-fidelity Internet simulation is necessary to properly evaluate these defenses.Current network simulators cannot be used to study Internet-scale events. They are general-purpose, packet-level simulators that reproduce too many details of network communication, which limits scalability. Even distributed versions of network simulators such as GTNetS and PDNS, designed for large-scale events, have limited scalability because each packet and its handling are simulated in minute detail. For example, PDNS requires powerful, 100+ CPU clusters, to simulate worm propagation with up to 1.28 M vulnerable hosts. Many researchers do not have an access to such a large cluster. Another drawback of the current network simulators is that they lack a built-in Internet model. Researchers that aim to simulate Internet-scale events must themselves assemble the Internet topology, and determine end-host communication patterns, link bandwidths and routes. The effort required to set up a realistic Internet model from scratch is considerable so many researchers adopt simplfied models (e.g., assuming infinite bandwidth links, assuming highly symmetric Internet topology etc.) which leads to incorrect results. The iSim work builds upon our recent achievements in creating an Internet-scale simulator of worm propagation events, called PAWS. PAWS is a distributed simulator, deployed on the Emulab testbed. This project will explore the potential of the PAWS simulator as a community resource.