The Traffic Engineering Benefits of Flexible Routing in International Networks

In the past decade, several countries have introduced or proposed flexible routing schemes for their national networks. In large networks with noncoincident busy hours and many alternate routes, the schemes provide, for a given number of circuits, greater throughput than hierarchical routing schemes. In addition, they provide better service when an unexpected event occurs. In this paper we study the extent of these benefits in small bilateral networks without non-coincident busy hours and with only a few alternate routes. A typical network with flexible routing can provide equivalent service consistently with 3-6% fewer circuits than the same network with hierarchical routing. Occasionally the savings are as high as 9%. With the same network, flexible routing can complete at least half of the calls blocked by hierarchical routing.