Shared backup protection based on aggregated information in WDM networks

A comparison between three schemes for the protection of lightpaths in wavelength-routed networks under the control of the GMPLS plane is presented. The protocols used to establish ER-LSP in GMPLS can be used in the optical domain to provision virtual lightpaths over pre-computed paths and for protection mechanisms deployment. The extensions for traffic engineering of the OSPF and RSVP protocols enable the planning of shared protection mechanisms. The first scheme considered is a simple dedicated protection scheme. The last two schemes are based upon shared protection wavelengths and can be supported by current protocols. The schemes have been evaluated using models that focus upon the relative merits of the protection schemes in terms of admission control for the lightpath requests. Path selection is of secondary interest. Results show that, for WDM networks with wavelength conversion, the shared protection mechanism using partial fibre information performs well and can be an alternative to the use of a complex shared backup scheme; it demands a minimal number of reserved protection wavelengths and offers relatively low rejection probability.