Achieving Near-Optimal Traffic Engineering Solutions for Current OSPF/IS-IS Networks

Traffic engineering aims to distribute traffic so as to "optimize" some performance criterion. This optimal distribution of traffic depends on both the routing protocol and the forwarding mechanisms in use in the network. In IP networks running the OSPF or IS-IS protocols, routing is over shortest paths, and forwarding mechanisms distribute traffic "uniformly" over equal cost shortest paths. These constraints often make achieving an optimal distribution of traffic impossible. In this paper, we propose and evaluate an approach that can realize near optimal traffic distribution without changes to routing protocols and forwarding mechanisms. In addition, we explore the trade-off that exists between performance and the configuration overhead that our solution requires. The paper's contributions are in formulating and evaluating an approach to traffic engineering in IP networks that achieves near-optimal performance while preserving the existing infrastructure