Investigating Performance Metrics for Evaluation of Content Delivery Networks

Abstract

Content Delivery Networks are one of the most common services in order to overcome performance problems caused by massive data requests in popular web applications. CDNs improve clients’ perceived quality of service by placing replica servers scattered around the globe and consequently redirecting users to closer servers. While CDNs’ ultimate goal is to improve the performance of data delivery, their own efficiency can also be an issue to investigate. Due to the complexity of these services, plenty of factors can impact the performance of CDNs. As a result, the efficiency of CDNs can be measured using various metrics. In this paper we review some of the well-known performance metrics in the literature for evaluating CDNs. We also present some other measures including Fairness and Content Travel. In order to attain an overall insight about a CDN, a Cost Function is also presented which incorporates most of the metrics in a single formula.