A hierarchical model for BGP routing policies
BGP routing policies are mainly used by network operators to enforce business relationships between Autonomous Systems (AS), and to prefer some routes over others. In this paper, we propose a hierarchical policy model to express each policy at the most appropriate level of abstraction. The model is structured around chains of filters that apply at a specific level of abstraction. To validate our approach, we implemented the model in a Java prototype and used it to reproduce several network-wide routing policies. In all studied networks, the model produced a high-level view of routing policies while preserving their semantics. Our model offers numerous advantages to network operators including, but not limited to, a better network documentation, an improved understanding of routing policies, redundancy suppression, and an easier way of managing their network.