A network management system can be configured to identify routes for satisfying a set of demands on an optical communication network using layer graph(s). The layer graph edges can have edge scores that indicate a cost of the edge. The network management system can generate the layer graph(s) using a network graph that represents the optical communication network and an associated sets of available frequency slots. The network management system can iteratively identify candidate path(s) on the layer graph(s) that correspond to each of the demands and determine a cost for each candidate path using the edge scores. In each iteration, the network management system can select the lowest cost candidate path, update the layer graph(s) based on this selection, and update the candidate paths for the remaining demands as needed. The network management system can similarly generate restoration paths for each of the demands.