Impairment-Aware Resource Allocation in Translucent Optical Networks Open Access
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Wavelength Division Multiplexing (WDM)-based optical networks are ideal candidates for core backbone networks because of their ability to carry large amounts of traffic. Optical amplification has increased the reach of long-haul optical links. Nevertheless, it is impossible today to construct a truly optical network without converting optical signals to electrical signals and regenerating them, because of the deleterious effects of physical impairments such as amplifier noise, dispersion, and non-linear effects such as four-wave mixing and cross-phase modulation. Regenerators (called 3R regenerators because of their function of reamplification, retiming, reshaping) can clean up the accumulated impairments by performing an Optical-Electrical-Optical (OEO) conversion and processing the electrical signal. Being expensive devices, these regenerators are expected to be sparsely located in the network, and networks with sparse regeneration capabilities are called translucent optical networks. Modern-day optical network customers (which are mainly core network routers) demand connections with heterogeneous bandwidth requirements. A Mixed Line Rate (MLR) optical network serves this purpose very well. Next-generation optical transport networks are also likely to include multiple domains with diverse technologies, protocols, granularities, and carriers. In such networks, the problem of routing and wavelength assignment (RWA) aims to find an adequate route and wavelength(s) for lightpaths carrying end-to-end service demands subject to scalability constraints. The first part of this dissertation presents our work on resource allocation algorithms for single-domain and multi-domain translucent optical networks.The second part of the dissertation addresses problems on a new technology - elastic optical networking through Optical Orthogonal Frequency-Division Multiplexing (OOFDM). A specific problem that we consider is the impairment-aware embedding of virtual networks in an elastic optical network. Virtualization improves the efficiency of networks by allowing multiple virtual networks to share a single physical network's resources. The last part of the dissertation presents new analytical models to calculate the connection blocking probability for three typical regeneration node allocation policies. The first policy allocates regeneration nodes when the lightpath needs either regeneration or wavelength conversion while the other two allocation policies allocate regenerators only for one of the two reasons.