Understanding cache dynamics in the network: a software approach

Abstract

Complex time-varying load dynamics can be found at a network cache. This is because data requests carried by thousands of connections over diverse network paths load the cache by many read (and sometimes) write operations. User populations with a heterogeneity of request patterns and delay requirements induce hitrate dynamics at the network and cache interface. Content dynamics are further compounded by the existence of local expurgation policies and dimensioning decisions for each cache on a network path. Multi-level caches on the same network path may cause inter-cache dynamics of their contents. Finally, since the cache is inevitably part of a networked system, there is a complex dynamic relation between the cache hitrate and the network traffic. All that said, buffering events during media replay are still commonplace and annoying, caching solutions may be at the root of problem or be part of a solution such as in a CDN. Either way, we present a joint simulation-visualization tool to give some insight into the dynamics of network caching.