Efficiency of Caching and Content Delivery in Broadband Access Networks

This chapter discusses the efficiency aspects of caching systems. It explains the applications and performance aspects of caching. This is followed by a discussion on user request pattern for Internet content that can be characterized by Zipf laws with positive effect on cache hit rates. Traditionally, there are two main application areas for caching: Caching by operation systems of computers in fast storage in order to shorten delays in data access, and Web caching in order to shorten transport paths. The chapter evaluates the influence of caching strategies on the hit rate and reveals large differences between simple approaches and more elaborate methods, which combine statistics on requests in the past with adaption capability to changing popularity of objects. It concludes with a discussion on traffic management and optimization via content delivery (CDN) and peer‐to‐peer (P2P) overlays on the network infrastructure.