The Effectiveness of Request Redirection on CDN Robustness

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 the best published CDN technology, yet user-perceived response latency remains low and the system scales well with the number of servers.

• Type: Conference
• Year: 2002
• Where: OSDI
• Authors: Limin Wang, Vivek S. Pai, Larry L. Peterson
• Keywords: Large-scale Detailed Simulations, Operating System, OSDI 2002, Server Load, User-perceived Response Latency