A method of computing end-to-end paths through a network comprising a plurality of network domains (401, 402, 403), the method comprising the steps of: computing a path segment within a network domain of the plurality of network domains (401, 402, 403) using a child path computation element associated with the network domain, wherein each network domain of the plurality of network domains (401, 402, 403) is associated with a respective child path computation element; and computing an end-to-end path across the plurality of network domains (401, 402, 403) using a parent path computation element that computes the end-to-end path in conjunction with the plurality of child path computation elements (404, 405, 406) associated with the respective plurality of network domains (401, 402, 403), wherein the parent path computation element computes the end-to-end path by joining a plurality of path segments computed by the plurality of respective child path computation elements (404, 405, 406); characterised by computing a global identifier for the end-to-end path and identity of border nodes of each network domain that forms part of the end-to-end path, using the parent path computation element, wherein the global identifier is used as an egress label by an egress node of the network domain to reach to an ingress node of another network domain forming part of the end-to-end path; passing the global identifier and the identity of the border nodes to the plurality of respective child path computation elements (404, 405, 406), wherein each of the plurality of respective child path computation elements (404, 405, 406) computes its respective path segment between the border nodes of its respective network domain and passes the respective path segment to an ingress node of its respective network domain; and establishing, by each of the plurality of respective child path computation elements (404, 405, 406), a respective Label Switched Path, LSP, between the border nodes for its path segment within its respective network domain, wherein each respective LSP has an LSP identifier comprising a local identifier computed by the respective child path computation element and the global identifier. computing a path segment within a network domain of the plurality of network domains (401, 402, 403) using a child path computation element associated with the network domain, wherein each network domain of the plurality of network domains (401, 402, 403) is associated with a respective child path computation element; and computing an end-to-end path across the plurality of network domains (401, 402, 403) using a parent path computation element that computes the end-to-end path in conjunction with the plurality of child path computation elements (404, 405, 406) associated with the respective plurality of network domains (401, 402, 403), wherein the parent path computation element computes the end-to-end path by joining a plurality of path segments computed by the plurality of respective child path computation elements (404, 405, 406); characterised by computing a global identifier for the end-to-end path and identity of border nodes of each network domain that forms part of the end-to-end path, using the parent path computation element, wherein the global identifier is used as an egress label by an egress node of the network domain to reach to an ingress node of another network domain forming part of the end-to-end path; passing the global identifier and the identity of the border nodes to the plurality of respective child path computation elements (404, 405, 406), wherein each of the plurality of respective child path computation elements (404, 405, 406) computes its respective path segment between the border nodes of its respective network domain and passes the respective path segment to an ingress node of its respective network domain; and establishing, by each of the plurality of respective child path computation elements (404, 405, 406), a respective Label Switched Path, LSP, between the border nodes for its path segment within its respective network domain, wherein each respective LSP has an LSP identifier comprising a local identifier computed by the respective child path computation element and the global identifier.