A fresh look at inter-domain route aggregation

We present three route aggregation strategies to scale the Internet´s inter-domain routing system. These strategies result from a keen understanding on how the customer-provider, peer-peer routing policies propagate routes belonging to long prefixes in relation to how they propagate routes belonging to shorter prefixes that cover the long ones. The first strategy, Coordinated Route Suppression, requires coordination between the Autonomous Systems (ASs) of the Internet, and we present a protocol to perform such coordination. The second strategy, No Import Provider Routes, does not require any coordination between the ASs, but benefits only some of them. The third strategy, Implicit Long Routes, does not rely on any coordination between the ASs either and it is the most efficient strategy. However, it presupposes modifications to the way routers build their forwarding tables. We evaluate the three route aggregation strategies over a publicly available description of the Internet topology and on synthetically generated Internet-like topologies. The results are very promising, with savings in the amount of state information required to sustain inter-domain close to the optimum possible.