ISPs as Nodes or Sets of Links?
The authors consider the contract-switching paradigm for studying the inter-domain traffic engineering problem. In the contract-switching paradigm, each ISP in the Internet is abstracted as a set of edge-to-edge contract links. They formulate the optimal routing problem for the contract-switching paradigm by considering three objectives, namely: maximizing throughput, minimizing delay, and minimizing bandwidth usage. They solve the optimization problems on realistic network topologies and show that the routing solutions developed using the contract switching paradigm provides significant improvement in performance compare to the BGP routing framework with respect to the three objectives.