Caching of popular content during off-peak hours, in storage memories distributed across the network, is a strategy to reduce network loads during peak hours. Recent work has shown significant benefits of designing such caching strategies not only to deliver part of the content locally, but also to provide coded multicasting opportunities even among users with different demands. 
Previous work focused on networks with a single layer of caches. In this work, we consider a hierarchical network with two layers of caches, and propose a caching scheme with a simple, intuitive structure that exploits coded multicasting opportunities in both layers of the network.  Furthermore, we show that the transmission rates in each layer are within a constant multiplicative and additive gap of the optimum.