Benefits of fine QoT-estimator to dimension spare resources in automatic restorable networks

In automatically restorable optical networks, the control plane has to detect a failure and send traffic through recovery paths. A successful restoration is guaranteed if an appropriate number of spare resources is available in the network. Usually a quality of transmission (QoT) estimator helps estimate the number of opto-electronic devices to guarantee transparent connection, within a given confidence level. The interest of a fine QoT-estimator lies in the reduction of the number of opto-electronic resources required to set-up a transparent connection. During the planning phase, this reduction enables the design of functional and economically attractive networks. The interest of fine QoT-estimators is shown also when planning failure-resilient networks: thanks to the knowledge of physical performance depending on the chosen channel, on the kind of traversed devices and so on, it is possible to share resources; this is particularly interesting when considering node constraints, such as the limited number of add/drop capabilities.