1. A Path Computation Element (PCE) comprising: a receiver configured to receive a path computation request from a path computation client (PCC), the path computation request requesting computation for a first path from a head end node to a tail end node, wherein the PCE is a child PCE positioned in a first domain, and wherein the head end node is positioned in the first domain and the tail end node is positioned in a second domain; a processor coupled to the receiver and configured to: forward the path computation request to a parent PCE responsible for computing the first path across the first domain and the second domain; receive a path computation response from the parent PCE indicating domains that the first path traverses; compute a second path within the first domain based on the path computation response from the parent PCE, wherein the second path is a portion of the first path; and assign a first Multiprotocol Label Switching (MPLS) label for a Software Defined Network (SDN) compatible node in the second path, wherein the first MPLS label is associated with a label switched path (LSP) that traverses each node in the second path; and a transmitter coupled to the processor and configured to transmit the first MPLS label directly to the SDN compatible node via PCE protocol (PCEP).