Intelligent and scalable routing in multi-domain optical networks

A method of extending the control plane to a metro sub-domain for a network having a transport plane for carrying subscriber traffic within end-to-end connections, and a control plane for managing at least a portion of resources of the transport plane allocated to the connections. A first set of control-plane enabled nodes of the network is designated as core nodes, each core node being operable to route subscriber traffic between a pair of neighbor core nodes in the network. A second set of control-plane enabled nodes of the network is designated as metro nodes, each metro node being connected to a core node and operating as a sub-domain of the network. Each core node that is connected to at least one metro node is designated as a host node. The host node is controlled to advertise summary information of its connected metro nodes to other core and metro nodes in the network, thus making it possible to extend control plane function to the metro nodes that can calculate connection routes, set-up/tear-down connections and perform connection failure recovery functions.