Caching and Neutrality

We are used to defining network neutrality as absence of traffic differentiation, like policing or shaping. These mechanisms, however, are often not what determines end-users' quality of experience (QoE). Most content today is accessed through edge caches, operated by cloud providers, but located near or inside the end-user's Internet Service Provider (ISP). Hence, the end-users' QoE is often determined by the interplay between the caching system (controlled by the cloud provider) and the network between edge cache and end-user (controlled by the eyeball ISP). So, we argue that an obvious point where differentiation may occur, and where transparency and neutrality may be desirable is the caching system; and that we (as a community) should perhaps consider notions of neutrality that capture the connection between caching and QoE.