Routing path calculation apparatus and methods are disclosed. Calculation of routing paths within different routing areas of a communication system is handled by respective routing path calculation devices. Multiple devices may be requested to perform respective routing path calculations for segments of a routing path between endpoints in different routing areas. Recalculations may be requested from the same or different devices in the event of a change in a routing area that affects a segment of a routing path. A routing path calculation device, whether or not in this type of distributed routing path calculation system, may determine whether a previously configured path exists between an intermediate node of a calculated routing path, and take the previously configured path into account in calculating the routing path if it is determined that a previously configured path exists. The previously configured path may be an Interior Gateway Protocol (IGP) shortcut, for example.