I will discuss the problem of building fast, programmable routers. I will present RouteBricks, a high-end router architecture that consists entirely of commodity servers. RouteBricks achieves high performance by parallelizing router functionality both across multiple servers and across multiple cores within a single server; it is fully programmable using the familiar Click/Linux environment. I will also present RB4, our 4-server prototype that routes at 35Gbps; this routing capacity can be linearly scaled through the use of additional servers.