Routing and wavelength assignment algorithms for translucent optical networks

摘要

Due to transmission impairments, optical regeneration is needed to extend the length of a lightpath beyond its transparent length. Spare transmitter (Tx) and receiver (Rx) modules in an optical network node can be used for optical regeneration. A Max-spare algorithm for locating the regeneration nodes for a lightpath is proposed and compared with a Greedy algorithm in conjunction with two routing algorithms, namely, wavelength weighted (WW) and length weighted (LW) routing algorithms. Through simulation we find that significant number of lightpaths that cannot be established due to the violation of transparent length can be established if the regeneration algorithm is used to select transit nodes that have spare Tx and Rx for 3R regeneration. The translucent optical network with limited number of transceivers can still perform close to a transparent optical network with full set of transceivers. We find that for the same routing algorithm, the Max-spare algorithm yields better results than the Greedy algorithm. In addition; for the same regeneration nodes selection algorithm, the WW algorithm has better performance than the LW algorithm.