Evaluating the utility of content delivery networks

Abstract

Content Delivery Networks (CDNs) balance costs and quality in services related to content delivery. This has urged many Web entrepreneurs to make contracts with CDNs. In the literature, a wide range of techniques has been developed, implemented and standardized for improving the performance of CDNs. The ultimate goal of all the approaches is to improve the utility of CDN surrogate servers. In this paper we define a metric which measures the utility of CDN surrogate servers, called CDN utility. This metric captures the traffic activity in a CDN, expressing the usefulness of surrogate servers in terms of data circulation in the network. Through an extensive simulation testbed, we identify the parameters that affect the CDN utility in such infrastructures. We evaluate the utility of surrogate servers under various parameters and provide insightful comments. Copyright 2009 ACM.