Request-Routing Trends and Techniques in Content Distribution Network

Content Distribution Networks (CDNs) have been developed and evolved to meet the growing commercial need for efficient and secure delivery of content over the Internet. Several proprietary CDN systems are now operating successfully, fulfilling the commercial demands to a certain extent. The protocols and algorithms used in these systems are mostly of proprietary nature and not standardized. Furthermore, the effectiveness of these protocols and algorithms has not yet been subject to analysis and exhaustive performance testing. However, the IETF Content Distribution Internetworking Group (CDN-WG) has begun the process of specifying the requirements and standardizing the protocols for CDNs. This paper presents an overview of Content Distribution Networks and then describes and analyzes different request routing techniques that have been developed by researchers so far to date.