《Optimum Caching Strategies for a Telco CDN》.pdf

◆ Optimum Caching Strategies for a Telco CDN Danny De Vleeschauwer and Dave C. Robinson In order to cope with the rapidly increasing video traffic (both downloaded and streamed) resulting from Internet TV, a telecommunications company (telco) can deploy a network of caches, which sit closer to the user than the point-of-presence of a traditional content distribution network (CDN), like Akamai or Limelight Networks. This network of highly distributed caches, often referred to as a telco CDN, is a network enabler that saves a huge amount of traffic on the links toward the Internet by handling user requests locally without having to retrieve data from the origin server. Because for Internet TV the set of available content is huge and rapidly evolving, the choice of the caching algorithm and cache collaboration strategy can have a considerable impact on the reduction in traffic. The caching algorithm decides which objects to cache, and the cache collaboration strategy, at times in combination with preloading, determines how cacheable items are propagated throughout the telco CDN. In this paper we determine the best combination of a caching algorithm and a cache collaboration strategy for a telco CDN. © 2011 Alcatel-Lucent. Introduction The amount of traffic transported over the during which the user reads or thinks about the con- Internet has been increasing steadily [13]. In recent tent just downloaded—in the former, the content is years this increase has been driven by a surge in con- consumed (i.e., watched, heard) as it is downloading. sumption of video over the network. Not only are It follows that video cannot rely on statistical multi- there more video components embedded in tradi- plexing as much as data can, and this, consequently, tional Web pages (e.g., news sites with video footage), puts even more stress on the network. more video services are also offered ove