Optimal Device Device-Aware Caching
Abstract: Caches in Content-Centric Centric Networks (CCN) are increasingly adopting flash memory based storage. The current flash cache technology stores all files with the largest possible “expiry date,� i.e., the files are written in the memory so that they are retained for as long as possible. This, however, does not leverage the CCN data characteristics where content is typically short short-lived lived and has a distinct popularity profile. Writing files in a cache using the longest retention time damages the memory device thus reducing its lifetime. However, writing using a small retention time can increase the content retrieval delay, since, at the time a file is requested, the file may already have been expired from the memory. This Thi motivates us to consider a joint optimization wherein we obtain optimal policies for jointly minimizing the content retrieval delay (which is a network-centric network objective) and the flash damage (which is a device device-centric centric objective). Caching decisions now not ot only involve what to cache but also for how long to cache each file. We design provably optimal policies and numerically compare them against prior policies.