1. A method for determining traffic flow availability, the method comprising: receiving an indication of a physical topology comprising a plurality of physical links, a logical topology comprising a plurality of logical links between a plurality of nodes, and a plurality of traffic flow demands; receiving a cross-layer network model that maps the logical topology to the physical topology; iteratively, for a predetermined number of cycles: generating a failure sample indicating a failure of a plurality of physical links in the physical topology; updating the logical topology model responsive to the failure of the plurality of plurality links in the failure sample and the cross-layer network model; and determining, with a traffic engineering simulator, if the updated local topology model is capable of satisfying the plurality of traffic flow demands.