Soft protection in optical networks with variable-code-rate transceivers

Future flexible transceivers will be able to adapt their transmission parameters according to the channel and traffic conditions. Many recent publications propose to adapt modulation format and transmission rate, but very few address variable-rate FEC. Variable-code-rate transceivers provide an efficient trade-off between transmission rate and reach, enabling advanced networking features such as soft protection, in which the protection lightpath operates at a lower data rate than the corresponding working lightpath, in a way to avoid regeneration. This paper discusses the main concepts behind soft protection in networks with variable-code-rate transceivers, and evaluates its performance in networks of different dimensions.