Performance of best effort shared path protection mechanism under physical impairments in WDM networks

Due to high data rate, failures can imply in great amount of data loss in wavelength division multiplexing (WDM) networks, requiring protection mechanisms to be employed. In shared protection, a protection path can be used by different associated working lightpaths given that these lightpaths have no common link. Transparency and switching in all-optical networks causes physical impairments which can significantly degrade the signal quality. If the signal quality in a path is below acceptable values, this path cannot be used by incoming requests for lightpath establishment. This paper investigates the impact of PMD, ASE and crosstalk physical impairments on the efficacy of best effort shared path protection mechanisms. Results derived via simulation point out that shared path is ineffective at rates higher than 10 Gbps and that Randon Pick is the most appropriate policy to be used in wavelength assignment.