Robust Validation of Network Designs under Uncertain Demands and Failures

A key challenge confronting wide-area network architects is validating that their network designs provide assurable performance in the face of variable traffic demands and failures. Validation is hard because of the exponential, and possibly non-enumerable, set of scenarios that must be considered. Current theoretical tools provide overly conservative bounds on network performance since to remain tractable, they do not adequately model the flexible routing strategies that networks employ in practice to adapt to failures and changing traffic demands. In this paper, we develop an optimizationtheoretic framework to derive the worst-case network performance across scenarios of interest by modeling flexible routing adaptation strategies. We present an approach to tackling the resulting intractable problems, which can achieve tighter bounds on network performance than current techniques. While our framework is general, we focus on bounding worst-case link utilizations, and case studies involving topology design, and MPLS tunnels, chosen both for their practical importance and to illustrate key aspects of our framework. Evaluations over real network topologies and traffic data show the promise of the approach.