Load balancing through efficient distributed content placement

The concept of content distribution networks (CDNs) has recently been introduced to enhance the delivery of bandwidth-intensive multimedia content to end users. In a CDN architecture, the content is replicated from the origin server to so-called surrogate servers at the edge of the Internet, to improve the quality of service and optimise network bandwidth usage. The introduction of peer-to-peer (P2P) architectures, where all nodes fundamentally play equal roles, enables self-organisation of the CDN and automatic recovery in case of node failures. To optimise the distribution of the content over the different surrogate servers, replica placement algorithms (RPAs) have been developed. In this paper, we present two distributed RPAs for CDNs. We will demonstrate that they further improve CDN performance by reducing the server load and the bandwidth usage. The introduction of link costs allows these algorithms to additionally support load balancing on the network links.