Asymmetric optical connections for improved network efficiency

Links in an IP network are unidirectional but currently are routed over bidirectional optical circuits with identical A → Z and Z → A capacities. Potentially there could be savings if the two directions of an optical circuit could be treated independently. In this study of possible savings, we have quantified the asymmetry of traffic on a current large IP backbone. A theoretical greenfield network with similarly asymmetric traffic is modeled, and it is shown that the use of unidirectional circuits to satisfy traffic demands provides significant equipment savings. We consider this study of the benefits of this approach to be a first step in deciding whether it makes economic sense to tackle the hurdles that would face such a major change in network design and operations.