The Effectiveness of Request Redirection on CDN Robustness
Report ID: TR-654-02Author: Pai, Vivek / Peterson, Larry / Wang, Limin
Date: 2002-06-00
Pages: 14
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Abstract:
It is becoming increasingly common to construct network services using redundant resources geographically distributed across the Internet. Content Distribution Networks are a prime example. Such systems distribute client requests to an appropriate server based on a variety of factors---e.g., server load, network proximity, cache locality---in an effort to reduce response time and increase the system capacity under load. This paper explores the design space of strategies employed to redirect requests, and defines a class of new algorithms that carefully balance load, locality, and proximity. We use large-scale detailed simulations to evaluate the various strategies. These simulations clearly demonstrate the effectiveness of our new algorithms, which yield a 60-91% improvement in system capacity when compared with published state-of-the-art CDN technology, yet user-perceived response latency remains low and the system scales well with the number of servers.