Label prioritization in GMPLS-centric all-optical networks

When establishing lightpaths in an all-optical DWDM network, it is possible that concurrent lightpath requests will block one another if the lightpaths attempt to reserve the same wavelength on the same link. In this paper, we propose a novel signaling mechanism, referred to as label prioritization, which attempts to reduce the backward-link blocking in GMPLS-centric all-optical networks by assigning different priorities to the suggested wavelengths (labels) of each connection request. The prioritization of wavelength encourages concurrent lightpath requests to choose different wavelengths, thereby reducing the possibility that the requests will be blocked. The label prioritization mechanism consists of a signaling extension to GMPLS to support the label prioritization and a modification in the optical switch controller to support the signaling extension. Simulation results show that the label prioritization method can effectively reduce wavelength conflicts.