Content-peering dynamics of autonomous caches in a content-centric network

A future content-centric Internet would likely consist of autonomous systems (ASes) just like today´s Internet. It would thus be a network of interacting cache networks, each of them optimized for local performance. To understand the influence of interactions between autonomous cache networks, in this paper we consider ASes that maintain peering agreements with each other for mutual benefit, and engage in content-level peering to leverage each others´ cache contents. We propose a model of the interaction and the coordination between the caches managed by peering ASes. We address whether stable and efficient content-level peering can be implemented without explicit coordination between the neighboring ASes or alternatively, whether the interaction needs to rely on explicit announcements of content reachability in order for the system to be stable. We show that content-level peering leads to stable cache configurations, both with and without coordination. If the ASes do coordinate, then coordination that avoids simultaneous updates by peering ISPs provides faster and more cost efficient convergence to a stable configuration. Furthermore, if the content popularity estimates are inaccurate, content-level peering is likely to lead to cost efficient cache allocations. We validate our analytical results using simulations on the measured peering topology of more than 600 ASes.