Aggressive Rank Accounting for End-to-End Lightpath Establishment in Multi-Domain WDM Networks

In multi-domain WDM networks, a lightpath establishment method based on rank accounting in order to establish end-to-end lightpaths without wavelength conversion has previously been proposed. In this method, the end-to-end lightpaths are established with small blocking probability based on ranking databases for wavelengths; however, the performance of the method deteriorates when the ranking databases are not frequently updated. Therefore, in this paper, we propose aggressive rank accounting (ARA). In this method, every time a lightpath establishment is processed, ranking databases for multiple nodes are updated simultaneously. In order to update the database for each node effectively, edge-node information is used, in addition to wavelength-state information. First, from the edge-node information, accuracies of the wavelength-state information for each node are computed. Then, the ranking database for each node is updated with the wavelength-state information and the computed accuracies. Numerical examples show that the ARA method provides smaller blocking probability than the conventional, conservative method when end-to-end lightpaths are not frequently established. In addition, the ARA method has a 60% lower blocking probability than the conservative method. Finally, we investigate parameter setting and show that the ARA method still provides smaller blocking probability even if routes of the end-to-end lightpaths change.