Towards Content Distribution Networks with Latency Guarantees

This paper investigates the performance of a content distribution network designed to provide bounded content access latency. Content can be divided into multiple classes with different configurable per-class delay bounds. The network uses a simple distributed algorithm to dynamically select a subset of its proxy servers for different classes such that a global per-class delay bound is achieved on content access. The content distribution algo- rithm is implemented and tested on PlanetLab [24], a world-wide distributed Internet testbed. Evaluation results demonstrate that despite Internet delay variability, subsecond delay bounds (of 200-500ms) can be guaranteed with a very high probability at only a moderate content replication cost. The distribution algorithm achieves a 4 to 5 fold reduction in the number of response-time violations compared to prior content distribution approaches that attempt to minimize average latency. To the authors� knowledge, this paper presents the first wide-area perfor- mance evaluation of an algorithm designed to bound maximum content access latency, as opposed to optimizing an average performance metric.

Huang, Chengdu, and Tarek Abdelzaher. "Towards Content Distribution Networks with Latency Guarantees." University of Virginia Dept. of Computer Science Tech Report (2004).