Internet Service Providers (ISPs) express complex policies, affecting everything from business relationships with their neighbors to traffic engineering, scalability, and security, by configuring the Border Gateway Protocol (BGP). However, the routing architecture within an ISP, coupled with the multi-step BGP route-selection algorithm running on the routers, imposes significant restrictions on the policies that can be realized in practice.

In this paper, we present Morpheus, a modular, open routing platform that addresses these limitations by changing the way BGP routes are propagated and selected within an ISP. With Morpheus, network operators can realize many useful policies that are infeasible today through flexible composition of multiple (possibly third-party developed) policy modules, and programming the route-selection algorithms. Morpheus can be readily deployed without requiring changes in other domains.