Network design and protection in light-trail networks

The light-trail architecture provides a novel solution to address IP-centric issues at the optical layer. By incorporating drop and continue functionality, overlaid with a light-weight control protocol, light-trails enable efficient sharing of network resources, support subwavelength traffic and minimize network costs. In this work, we investigate the network design and survivability problem in such networks in the presence of multigranularity subwavelength traffic subject to non-bifurcation constraints. We first establish the NP-Completeness of the light-trail routing problem by reduction from a Hamiltonian path problem. We propose three heuristics for light-trail network design and observe their performance with limited network resources. We study the effect of tunable and fixed transceiver equipments on network throughput. We observe that our heuristics yield excellent wavelength utilization under moderate to heavy loads even in the presence of heavily fractional traffic. We propose two additional heuristics for shared and dedicated protection and conclude that with only a modest amount of spare capacity, full protection can be provided for single link failures.