Optimal cache placement with local sharing: An ISP guide to the benefits of the sharing economy

Traffic patterns on the Internet are changing, with video and user-generated content (UGC) taking an increasing share of the volume. The dramatic increase of content providers and content peering has shown to decrease the profit of ISPs. In this work, we suggest the use of a cooperative caching mechanism between peering ISPs to farther mitigate this problem. We devise a model for cooperative cache placement with global knowledge, and design a solution for total objects placement that maximizes the demand satisfied from local or shared cache, under the following constraints: (1) The local demand is known at each ISP; (2) ISPs share only if they can satisfy at least the same demand as before the sharing. We introduce sharing cost, reciprocity, and fairness constraints. Through extensive experiments that are based on typical demand distribution, we demonstrate the clear benefits of sharing for reducing costs at ISPs, with an increase of available content in the cache of up to 35%.