Transport network paths are typically bidirectional and symmetrical. In multi-protocol label switching (MPLS) and generalized MPLS (GMPLS) mechanisms, independent labels are distributed for bidirectional paths. Thus, the requirement of the MPLS transport profile (MPLS-TP), which is a new transport technology, could not be satisfied efficiently. A novel label distribution mechanism for bidirectional paths in MPLS-TP networks is proposed. Labels distributed by the mechanism are symmetrical and can reflect the pairing relationship of the forward and backward directions of the transport path.