Differentiated quality-of-protection in survivable WDM mesh networks using p-structures

In this paper, we develop a design methodology of survivable Wavelength Division Multiplexing (WDM) networks based on pre-configured protection structures (p-structures) to support multiple classes of Quality-of-Protection (QoP). We elaborate a generic mathematical optimization method that could be used to provide n QoP levels R"i (i=1,...,n) provided that the network topology is (n+1)-connected. The added value of the p-structure approach is studied through the analysis of the required protection capacity to efficiently meet the needs of the supported n QoP levels. Furthermore, the protection capabilities and shapes of the protection building blocks of the p-structure and p-cycle schemes are compared to each others in order to gain an insight into how the flexibility of the p-structure scheme helps in meeting the requirements of multiple QoP levels. The computation results show that, depending on the network connectivity, up to 150% of protection capacity can be saved if p-structures are used rather than p-cycles. The analysis of the shapes of the optimal p-structures shows that, depending on the targeted QoP levels, the optimal mix of p-structures is very often composed of large and small structures with high and low protection capabilities, respectively.