Experimental evaluation of the backup sharing aggressiveness for dynamic shared path protection in GMPLS transparent optical networks

This article focuses on the problem of dynamic and distributed shared path protection in GMPLS-enabled all-optical networks without wavelength conversion capability. Thus, both working and backup LSPs use the same wavelength for all the links in their respective paths (i.e., WCC). In this context, standard GMPLS OSPF-TE protocol does not convey the required routing information to deal with efficient network performance in terms of both resource usage and blocking probability. An interesting strategy consists in two integrated steps: first, to extend OSPF-TE protocol to disseminate, on a per link basis and for each wavelength, both its availability and its shareability as backup channel; second, to devise an on-line CSPF algorithm leading to reduce the blocking probability while maximizing resource usage. The latter is accomplished through the so-called backup sharing in which backup LSPs share pre-reserved resources as long as their respective working paths are link-disjoint. The experimental results are obtained within the ADRENALINE testbed, an intelligent GMPLS-enabled all-optical transport network, in terms of blocking probability, restoration overbuild and setup delay, under different network loads and variable backup sharing factor.