Highly reliable ultra long haul optical transport networks

As the demand in telecommunication traffic grows exponentially within the past few years, the concern for reliable telecommunication networks also grows rapidly. This is partly due to the heavier and heavier dependence of all aspects of our lives on the ability to communicate faster and efficiently. In the past, ring protection and 1+1 protection are always required to provide high availability. However, with the need to reduce capital expenditure and the demand for more efficient usage of resources for protection while keeping the availability similar to the ring networks, network designers need to have the capability to assess the end-to-end reliability of various design options in order to make intelligent and economical decision on network selection. This paper focuses on the reliability of different ring architectures, and the analysis and evaluation of the impact of the environment (fiber cuts), the networks operation conditions (span switching) and the maintenance (duration of span switching) on the availabilities of real highly reliable ring networks (4-fiber BLSR/DWDM). In this work, we apply our extended design methodology to generate highly reliable continental backbone network (4-fiber BLSR/DWDM). The network elements are modeled based to their internal configurations. Multiple ring network designs solutions are generated and their end-to-end reliability calculated. We then consider the environmental factors by varying the frequency of possible fiber cuts on the fiber links. The frequency of fiber cuts is increased when there is lack of diversity. The Operations practices are represented by the change in the frequency and duration of the span switch outages. Span switching outages may be increased also due links and nodes maintenance activities. The reliability of the different network solutions are analyzed and the sensitivities of the end-to-end demands availabilities due to these various parameters are determined and analyzed.