Due to its huge bandwidth, optical fibre is currently widely deployed to provide a variety of telecommunications services and applications. Wavelength-division multiplexing (WDM) has emerged as the technology of choice to harness the huge bandwidth available in an optical fibre. Traffic grooming supports efficient utilization of network resources by allowing sub-wavelength granularity connections to be groomed onto a single lightpath. Fault-tolerance for WDM networks is a major architectural and design issue as a single link failure can cause loss of an enormous amount of information. However, providing 100% guaranteed resilience to all types of traffic supported by existing and future networks may be unnecessary and wasteful in terms of resource utilization and cost efficiency. This chapter investigates the problem of dynamic traffic grooming for WDM networks under a differentiated resilience scheme. We propose two differentiated resilience schemes at different grooming levels— Differentiated Resilience at Lightpath (DRAL) level scheme, and Differentiated Resilience at Connection (DRAC) level scheme. These schemes explore different ways of provisioning backup paths and tradeoff between bandwidth efficiency and the number of required grooming ports. Both schemes support three resilience classes: dedicated protection, shared protection, and restoration. Simulation is carried out to evaluate and compare the two differentiated resilience schemes. Simulation results show that the DRAL scheme is not very sensitive to the changes in the number of grooming ports, while the DRAC scheme utilizes grooming ports more aggressively as it trades grooming ports for bandwidth efficiency in routing and grooming.
Minimizing Blocking Probability for the Multicast Routing and Wavelength Assignment Problem in WDM Networks: Exact Solutions and Heuristic Algorithms
