Abstract: An agile transparent network with a trail routing and switching (also called “engineering”) mechanism is provided that enables efficient use of regenerators and wavelengths available in the network, while maintaining a very efficient time-to-service. The trail engineering mechanism allows fast, automatic establishment of new connections based on the current network architecture, connectivity and loading and also on conditions in the connection request. Selection of regenerator sites and of the wavelengths used on each regenerator segment is performed with optimal use of current network resources, while ensuring that the quality of the selected trail is adequate for the respective call. The mechanism provides for both distance and performance balancing, and it optimizes the network response time.

Abstract: A connection between a source node and a destination node is automatically routed and switched in a WDM photonic network, on receipt of a connection request. A switching and routing mechanism selects a plurality of valid link paths using a path tree, where invalid branches are eliminated based on constraints received in the connection request, and on a link and path cost functions. A regenerator placement tree is used for determining a plurality of viable regenerator paths for each valid link path. On the regenerator placement tree, non-viable branches are eliminated based on constraints received with the request and on regenerator availability at the intermediate nodes along the respective path, and on the specification of these available regenerators. Next, the switching and routing mechanism assigns a set of wavelengths to each viable regenerator path, and estimates the performance of the path using a Q estimator.