A network control device (11, 110) comprising: a network interface; and a control unit comprising at least one processor configured to: allocate one or more subset of resources of an underlay network to each of one or more virtual networks established over the underlay network, wherein the one or more subset of resources allocated to a respective virtual network includes one or more nodes and one or more links of the underlay network to be used by the respective virtual network; generate a bitmask encoded with link administrative group information associated with the one or more links, wherein each bit of the bitmask corresponds to a different one of a plurality of link administrative groups defined on the network control device, and wherein each of the link administrative groups define a different grouping of the one or more subset of resources of the underlay network; and output, to a plurality of provider edge 'PE' routers that are participating in a respective virtual network, a routing protocol message to advertise, using Border Gateway Protocol-Link State 'BGP-LS' advertisements, the one or more subset of resources, wherein the routing protocol message includes a route target specified as the bitmask. a network interface; and a control unit comprising at least one processor configured to: allocate one or more subset of resources of an underlay network to each of one or more virtual networks established over the underlay network, wherein the one or more subset of resources allocated to a respective virtual network includes one or more nodes and one or more links of the underlay network to be used by the respective virtual network; generate a bitmask encoded with link administrative group information associated with the one or more links, wherein each bit of the bitmask corresponds to a different one of a plurality of link administrative groups defined on the network control device, and wherein each of the link administrative groups define a different grouping of the one or more subset of resources of the underlay network; and output, to a plurality of provider edge 'PE' routers that are participating in a respective virtual network, a routing protocol message to advertise, using Border Gateway Protocol-Link State 'BGP-LS' advertisements, the one or more subset of resources, wherein the routing protocol message includes a route target specified as the bitmask. allocate one or more subset of resources of an underlay network to each of one or more virtual networks established over the underlay network, wherein the one or more subset of resources allocated to a respective virtual network includes one or more nodes and one or more links of the underlay network to be used by the respective virtual network; generate a bitmask encoded with link administrative group information associated with the one or more links, wherein each bit of the bitmask corresponds to a different one of a plurality of link administrative groups defined on the network control device, and wherein each of the link administrative groups define a different grouping of the one or more subset of resources of the underlay network; and output, to a plurality of provider edge 'PE' routers that are participating in a respective virtual network, a routing protocol message to advertise, using Border Gateway Protocol-Link State 'BGP-LS' advertisements, the one or more subset of resources, wherein the routing protocol message includes a route target specified as the bitmask.