Protection in survivable WDM grooming network.

Abstract

Optical networks have been widely expected to fill the need for tomorrow's backbone networks because of the high bandwidth and highly predictable performance they promise. However, in recent years, the downturn of the economy has made the deployment of costly equipment to obtain very high bandwidth less immediately attractive. In the current context, research must address these realistic conditions, and this is part of the motivation for the area in which the research in this thesis is performed.

We propose a two-step approach to design, and show how this approach is suitable from both the grooming and the protection points of view. We adopt well-known heuristics from literature to perform stand-alone grooming and stand-alone protection at the virtual link level, enhancing the protection algorithm by adotping a failure independent routing but failure-specific wavelength assignment for protection virtual links. We show that in relative terms, the grooming performance of the protection design is already quite good due to this approach. However, protecting at the virtual link level invariably increases the grooming cost of the protection solution, and this cost can be significant at the node at which it is maximum. We go on to show how this can be countered by performing sub-wavelength protection. All our theoretical expectations are validated by numerical simulations.

Our results are as follows. Subwavelength protection can effectively use unutilized capacity in existing virtual topology. Proposed protection results in protection solution with less total amount of electronic processing from both individual traffic component and overall traffic component point of view. Proposed algorithm not only decreases the amount of electronic processing from protection solution, but also decreases amount of virtual link setup for protection. The implementation of the two-phase approach help reduce the computation time to find an effective protection solution. Numerical results show that proposed algorithm has performed well and produces similar effects on different traffic patterns and topologies.