A path construction method, characterized by comprising: predefining by a second PE node a plurality of transmission path descriptors, TPDs, wherein each TPD corresponds to an underlying transmission path supporting a Virtual Private Network, VPN, service; creating, by the second Provider Edge, PE, node, a first VPN with a first PE node, and determining a first TPD, from the plurality of TPDs, based on an underlying transmission path meeting a service requirement of the first VPN; advertising, by the second PE node, a first BGP Labeled Unicast, BGP-LU, route to the first PE node via an area border router, ABR, through a Multiprotocol-Border Gateway Protocol, MP-BGP, signaling channel, such that the first PE node is able to create a first Forwarding Equivalence Class, FEC, to Next Hop Label Forwarding Entry, NHLFE, FTN, forwarding entry corresponding to a first Forwarding Equivalence Class, FEC, based on the first BGP-LU route received, wherein the first FTN forwarding entry is associated with a label forwarding path identified by the first TPD for a first VPN message to reach a BGP next hop; wherein the first BGP-LU route carries the first TPD and a label corresponding to the first FEC, and the first FEC consists of the first TPD and a first prefix configured by the second PE node for the first BGP-LU route; advertising, by the second PE node, a first VPN route to the first PE node through the MP-BGP signaling channel, such that the first PE node is able to determine a label forwarding path to a first VPN Prefix based on the first TPD carried in the first VPN route received ; wherein the first TPD is configured to identify the label forwarding path for the first VPN message to reach the BGP next hop. predefining by a second PE node a plurality of transmission path descriptors, TPDs, wherein each TPD corresponds to an underlying transmission path supporting a Virtual Private Network, VPN, service; creating, by the second Provider Edge, PE, node, a first VPN with a first PE node, and determining a first TPD, from the plurality of TPDs, based on an underlying transmission path meeting a service requirement of the first VPN; advertising, by the second PE node, a first BGP Labeled Unicast, BGP-LU, route to the first PE node via an area border router, ABR, through a Multiprotocol-Border Gateway Protocol, MP-BGP, signaling channel, such that the first PE node is able to create a first Forwarding Equivalence Class, FEC, to Next Hop Label Forwarding Entry, NHLFE, FTN, forwarding entry corresponding to a first Forwarding Equivalence Class, FEC, based on the first BGP-LU route received, wherein the first FTN forwarding entry is associated with a label forwarding path identified by the first TPD for a first VPN message to reach a BGP next hop; wherein the first BGP-LU route carries the first TPD and a label corresponding to the first FEC, and the first FEC consists of the first TPD and a first prefix configured by the second PE node for the first BGP-LU route; advertising, by the second PE node, a first VPN route to the first PE node through the MP-BGP signaling channel, such that the first PE node is able to determine a label forwarding path to a first VPN Prefix based on the first TPD carried in the first VPN route received ; wherein the first TPD is configured to identify the label forwarding path for the first VPN message to reach the BGP next hop. <EOS>