WWW Cache Control Mechanism in the AI3 Satellite Network

Abstract

We propose a WWW cache control mechanism that adapts the traffic of satellite links and latency to retrieve a WWW object for the user. To prefetch a WWW object effectively reduces the latency of a satellite link; however, this technique also generates massive traffic and should be controlled. We use a control mechanism where the rim cache will decide whether to prefetch an object after observing the current traffic of satellite links in real time. The cache then decides which object should be prefetched, based on the users' access patterns. In addition, the hub cache distributes the frequently-accessed objects with multicast transmissions and improves hit ratio on rim caches. We adopted the mechanism for the AI3 satellite network, which connects several research organizations in Asia, and conclude that the proposed system improved the hit ratio of the cache 15% while reducing the mean retrieval time of an object 20%, compared to a conventional cache system.