Takayoshi Asakura

A Cache Replacement Method for Crowded Streaming Cache Servers Responding to Rapidly Changing Access Patterns

The emergence of high quality video streaming services over the Internet has caused significant increases in the volume of traffic. Until now, cache technologies that have deployed frequently requested content in the proximity of users to mitigate traffic have been widely deployed on the Internet to improve user experiences and make them more effective. However, even when a cached object becomes a candidate for eviction due to lower access frequency, the object cannot be evicted since it is locked in working status until delivery is completed. This degrades the cache hit ratio and it has recently become much more common in high access traffic environments. This paper proposes a new method of replacing caches, called scheduled eviction of lingering caches (SELC). SELC selects an eviction candidate object based on replacement latency and shuts new access out by redirecting the access to an origin server so as to unlock the object by completing delivery for existing requests. Consequently, SELC can preserve cache space for emerging content. The results we obtained from simulations indicated that the proposed method could improve the cache hit ratio of crowded cache servers in an environment of rapidly changing access frequency.