US Patent 10110438 Control plane discovery of services

A method for control plane discovery includes a plurality of network elements transmitting an outbound control plane communication to generate path information of a path through the network elements. The transmitting includes receiving, by an intermediate network element of the network elements, the outbound control plane communication on an optical layer ingress port, appending, by the intermediate network element, an intermediate network element identifier of the intermediate network element to the path information in the outbound control plane communication, and transmitting, by the intermediate network element, the outbound control plane communication via an electrical layer egress port based on the intermediate network element comprising a layer changing drop port. The method further includes the network elements receiving via the path, the path information via a returned control plane communication, storing the path information in the returned control plane communication, and operating a control plane using the path information.