Flash crowd mitigation via adaptive admission control based on application-level observations
Flash crowd mitigation via adaptive admission control based on application-level observations
复制标题
通过基于应用程序级观察的自适应准入控制来缓解闪光人群
DOI：
10.1145/1084772.1084776
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
J. Heidemann
中科院分区：
文献类型：
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作者：
Xuan Chen;J. Heidemann
我们设计了一种自适应的准入控制机制，网络预警系统（NEWS），以保护服务器和网络免受快闪人群的影响，并为最终用户保持高性能。NEWS从响应的性能下降中检测快闪人群，并通过自适应地接受传入请求来减轻快闪人群。我们通过仿真和试验台实验来评估NEWS的性能。我们首先在模拟中研究网络受限的场景。我们发现NEWS在20秒内就能发现快闪人群。通过丢弃32%；对于传入请求，NEWS保护目标服务器和网络免受过载，将响应包丢包率从25%降低到25%；2百分比;。对于被承认的请求，NEWS将其响应率提高了两倍。这种性能类似于在相同场景中部署的最佳静态速率限制器。我们还研究了检测间隔对NEWS性能的影响，表明它同时影响检测延迟和虚警率。我们进一步在试验台实验中考虑服务器内存有限的场景，确认NEWS在这种情况下也是有效的。我们还在实践中考察了NEWS流量监控的运行时成本，发现它消耗很少的CPU时间和相对较小的内存。最后，我们展示了NEWS有效地保护了旁观者的交通不受快闪人群的影响。
We design an adaptive admission control mechanism, network early warning system (NEWS), to protect servers and networks from flash crowds and maintain high performance for end-users. NEWS detects flash crowds from performance degradation in responses and mitigates flash crowds by admitting incoming requests adaptively. We evaluate NEWS performance with both simulations and testbed experiments. We first investigate a network-limited scenarion in simulations. We find that NEWS detects flash crowds within 20 seconds. By discarding 32&percent; of incoming requests, NEWS protects the target server and networks from overloading, reducing the response packet drop rate from 25&percent; to 2&percent;. For admitted requests, NEWS increases their response rate by two times. This performance is similar to the best static rate limiter deployed in the same scenario. We also investigate the impact of detection intervals on NEWS performance, showing it affects both detection delay and false alarm rate. We further consider a server memory-limited scenario in testbed experiments, confirming that NEWS is also effective in this case. We also examine the runtime cost of NEWS traffic monitoring in practice and find that it consumes little CPU time and relatively small memory. Finally, we show NEWS effectively protects bystander traffic from flash crowds.