Wresting Control from BGP: Scalable Fine-Grained Route Control

Today's Internet users and applications are placing increased demands on Internet service providers (ISPs) to deliver fine-grained, flexible route control. To assist network operators in addressing this challenge, we present the Intelligent Route Service Control Point (IRSCP), a route control architecture that allows a network operator to flexibly control routing between the traffic ingresses and egresses within an ISP's network, without modifying the ISP's existing routers. In essence, IRSCP subsumes the control plane of an ISP's network by replacing the distributed BGP decision process of each router in the network with a more flexible, logically centralized, appliction-controlled route computation. IRSCP supplements the traditional BGP decision process with an explicitly ranked decision process that allows route control applications to provide a per-destination, per-router explicit ranking of traffic egresses. We describe our implementation of IRSCP as well as a straightforward set of correctness requirements that prevents routing anomalies. To illustrate the potential of application-controlled route selection, we use our IRSCP prototype to implement a simple form of dynamic customer-traffic load balancing, and demonstrate through emulation that our implementation is scalable.