Routing is a black art in today's Internet. End users and ISPs alike have little control over how their packets are handled outside of their networks, stemming in part from limitations of the current wide-area routing protocol, BGP. We believe that many of these constraints are due to policy-based restrictions on route exportation. Separating forwarding policy from route discovery would allow users to select among the possibly many inter-AS paths available to them and enable ISPs to more effectively manage the end-to-end behavior of their customers' traffic. As a concrete mechanism for enforcing forwarding policy, we propose the concept of a network capability that binds together a path request, an accountable resource principal, and an authorizing agent. Network capabilities are central to Platypus, a loose source routing protocol we are designing, which composes network capabilities authorized by multiple ISPs to construct alternative inter-AS routes that can be independen...
Alex C. Snoeren, Barath Raghavan