Coverage-aware proxy placement for dynamic content management over the Internet

In an effort to differentiate service quality, service providers have resorted to employing Content Distribution Networks (CDNs) over the Internet CDNs deploy geographically distributed proxy servers which manage content on behalf of the service provider´s servers for better performance and enhanced availability. In this paper we explore the proxy placement problem for content distribution over the Internet. Its goal is to strategically place a number of proxies in the network to optimize certain criteria which improve performance of proxies. We motivate the various necessary factors and constraints that need to be taken into account for a good placement of proxies over the Internet which reflect real world scenario more accurately and which we claim hitherto has not been completely addressed. We introduce a novel concept of host coverage characterizing every Autonomous Systems (AS) and use this stable, coarse grained measure as a long-term estimate of the load being serviced by the proxy system. We then pose an optimal formulation of the proxy placement problem taking into consideration all the relevant factors. We propose a couple of proxy placement algorithms that solve the above problem and analyze their behavior. Finally we present the performance of those algorithms against the optimal solution and other schemes proposed in literature. We also study the stability of the proposed algorithms through a variety of experiments.