The advantages of transparent optical networks such as high capacity and low cost can be outweighed by their complex fault management and the high impact of the faults occurring within them. Indeed, transparent optical networks reduce unnecessary, complex, and expensive opto-electronic conversion, to the cost of having faults more deleterious and affecting longer distances than in opaque networks. Moreover, transparent optical networks have limited monitoring capabilities, which could hinder efficient and accurate fault detection and localization. Different approaches have been proposed in the literature to perform fault localization, targeting different fault scenarios (e.g. single/multiple faults or looking at the optical/higher layers), and considering different assumptions (e.g. ideal/existence of false or lost alarms). Furthermore, fault management depends on the placement of monitoring equipment, whose optimization has been studied and also presented in this chapter.
Topology Design of Transparent Optical Networks Resilient to Multiple Node Failures