Patent ID: 7774474

Claim:
A method for establishing communication between a control layer and a line layer, the line layer including a plurality of network elements having a data path via a plurality of interconnections, the control layer including a plurality of controllers, each controller corresponding to one of the network elements, the method comprising the steps of: (a) transmitting, from a first controller to a second controller, a control path set-up message, said control path set-up message including information identifying a first data path interconnection between a first network element and a second network element; (b) at said second controller, upon receiving said control path set-up message from said first controller querying the second network element for local state information relating to said first data path interconnection and modifying said control path set-up message to include said local state information which identifies a second data path interconnection between said second network element and a third network element; and (c) transmitting said modified control path set-up message from said second controller to another controller corresponding to said third network element; wherein step (a) includes tracing said first data path interconnection to obtain said information identifying said first data path interconnection; wherein said step of tracing includes identifying a first cross connection in said first network element corresponding to the data path.