Methods and apparatus to determine network link weights are disclosed. An example method disclosed herein to determine link weights for routing in a communication network comprises iteratively updating a plurality of vectors using a genetic algorithm, the vectors including a plurality of individual values decodable into possible link weights, and decoding a first one of the vectors updated using the genetic algorithm into a first plurality of link weights providing a possible routing of a load through the communication network, the load to be split among a plurality of paths having respective path lengths determined from the plurality of link weights, at least two of the paths having different path lengths.