Formulations for the RWA problem with traffic grooming, protection and QoS in WDM optical networks

The emergence of WDM technology has provided the explosive traffic growth on telecommunications networks. Although in future networks a request may require more than a single wavelength, in general, in today´s networks, the size of a single request tends to be much smaller than the capacity of a wavelength channel. Thus, the need for traffic grooming became evident. In this paper, we present formulations based on network flows and column generation for the problem of routing and wavelength assignment (RWA) with traffic grooming, protection and quality of service on optical networks in order to minimize the number of wavelengths used. This problem is NP-complete and exact approaches are commonly practicable only in small instances. In this study, the employment of advanced techniques such as column generation and branch-and-price led to solve the problem for instances of real-world network size.