Optimal configuration for BGP route selection

An Internet Service Provider must provide transit service for traffic between its customers and its providers and, at the same time, attempt to minimize network utilization and balance traffic according to the capacities of its border routers. Central to the selection of border routers for transit traffic flows is the Border Gateway Protocol (BGP) between Autonomous System (AS) peers, through which route advertisements for network prefixes determine the selection of border routers for each traffic flow. This paper examines the problem of determining an optimal set of border routers for the advertisement of network prefixes so as to minimize the cost of traffic across a transit service provider's network while maintaining egress bandwidth constraints at the border routers. Egress bandwidth constraints are considered because there is anecdotal evidence to suggest that the peering links between ASs are often bottleneck links in the Internet, and so the optimal utilization of these links is also critical. After precisely formulating the optimization problem in accordance with the operation of BGP, we relate the problem to the generalized assignment problem and develop heuristic solutions for solving it. Simulation results from an implementation show up to a 37% improvement in the utilization of the peering links when compared to hot potato routing.