Scheduling algorithms for a cache pre-filling content distribution network

Cache pre-filling is emerging as a new concept for increasing the availability of popular Web items in cache servers. According to this concept, Web items are sent by a "push-server" to the proxy cache servers, usually through a broadcast-based or a multicast-based distribution mechanism. One of the most difficult challenges is to design the scheduling algorithm of the push-server. This algorithm needs to determine the "broadcast scheduling map", namely which Web items to broadcast and when. In this paper we study the approach where every constant period of time each proxy cache analyzes the requests it has received in the past and determines which Web item it prefers to receive by broadcast and when. We formalize a related problem, called the "cache pre-filing push" (CPFP) problem, analyze its computational complexity, and describe efficient algorithms to solve it.