We consider the problem of wavelength reuse assignment and of routing in all-optical networks. Since the capacity of number of wavelengths of current optical communication devices are restraint, the optical wavelength reuse is the only solution for this issue. The problem is NP-complete and therefore does not have one and only solution. Several algorithms were proposed along the years on this subject. In this work we develop a metric for wavelength assignment algorithms in all-optical networks like deBruijn networks for instance. We derive an upper bound of traffic corresponding to connections in such a network. The bound depends on the number of edges of the network respectively. We compare the bound with the simple shortest path algorithm to test its validity. The simulation test result show that it is feasible to get several all-optical connections to each node in a large network using relatively limited number of wavelength compared with the number of traffic sources.