SURVIVABLE OPTICAL NETWORK DESIGN WITH UNAMBIGUOUS SHARED RISK LINK GROUP FAILURE LOCALIZATION

The ever increasing thirst for bandwidth and the strict reliability and timing requirements of applications requires new network resilience methods in the fault management of optical backbone networks. It is particularly critical when an all-optical backbone is in place owing to its high data rate along each fiber and transparency in the data plane. In order to ensure an infrastructure of providing services requiring high Quality of Service (QoS), precise modeling of core optical mesh networks is crucial. For this purpose, the Shared Risk Link Group (SRLG) concept is introduced for modeling physical and geographical dependency among seemingly unrelated link failures. There have been numerous studies showing various benefits of (1+1) dedicated protection, which is the widely deployed technology in current optical backbone. However, all of the methods seek the solution of the routing problem in a pre-defined form, which is rather inefficient to find the most flexible routing structure to the QoS needs of the customers. In the first part of this thesis, we introduce a mathematical model which generalizes all previously reported dedicated protection schemes, called Generalized Dedicated Protection (GDP). The routing solutions required to be resilient and robust against all failures in a list of SRLGs defined by the network operator for each QoS class based on operational premises. Based on the equipments available at the network nodes various aspects of the problem is investigated. To further generalize the GDP problem, the applicability of network coding is investigated, and shown to be efficient in practical scenarios. Owing to the mathematical operations required, network coding necessarily incurs some additional cost. However, the complexity of GDP with network coding is polynomial-time, thus, makes the proposed method for on-line routing possible. In the second part of this thesis, as the key point of rapid optical layer restoration, unambiguous failure localization using supervisory lightpaths in all-optical networks is discussed. Using the most flexible structures (called monitoring-trails), the M-trail Allocation Problem (MAP) is introduced in order to minimize the signaling complexity of failure localization. Sufficient conditions on code assignment for multi-link SRLGs are presented, which can be used in various research fields as the basis of algorithm design. The algorithms of the thesis covers various important application scenarios in the fault-management of all-optical networks, which were not addressed efficiently in the literature previously, i.e. unambiguously localizing SRLGs with heterogeneous number of links contained, including the node failure scenario. The impact of the results is demonstrated with publications in the most prestigious journals in our research field.