A method comprising: receiving, by a first network device, a route advertisement message (24, 25, 26) that includes an attribute for downstream allocation or upstream allocation, the attribute specifying information comprising: a plurality of next hops of a second network device for reaching a network destination in the route advertisement message, a plurality of forwarding semantics describing forwarding actions associated with respective ones of each of the plurality of next hops and respective next hop attributes of the plurality of next hops, and a field indicating whether the attribute is provided for downstream allocation or upstream allocation; in response to determining, by the first network device, that the field indicates the attribute is provided for upstream allocation: installing, by the first network device and based on the plurality of forwarding semantics, the plurality of next hops, the forwarding actions, and the next hop attributes to forwarding information stored by the first network device; and applying, by the first network device and based on the forwarding information, the forwarding actions to network traffic received by the first network device and destined for the network destination when forwarding the network traffic to one or more of the plurality of next hops; and in response to determining, by the first network device, that the field indicates the attribute is provided for downstream allocation, selecting the second network device to which to forward traffic based on one or more of the plurality of next hops of the second network device and the associated forwarding semantics. receiving, by a first network device, a route advertisement message (24, 25, 26) that includes an attribute for downstream allocation or upstream allocation, the attribute specifying information comprising: a plurality of next hops of a second network device for reaching a network destination in the route advertisement message, a plurality of forwarding semantics describing forwarding actions associated with respective ones of each of the plurality of next hops and respective next hop attributes of the plurality of next hops, and a field indicating whether the attribute is provided for downstream allocation or upstream allocation; a plurality of next hops of a second network device for reaching a network destination in the route advertisement message, a plurality of forwarding semantics describing forwarding actions associated with respective ones of each of the plurality of next hops and respective next hop attributes of the plurality of next hops, and a field indicating whether the attribute is provided for downstream allocation or upstream allocation; in response to determining, by the first network device, that the field indicates the attribute is provided for upstream allocation: installing, by the first network device and based on the plurality of forwarding semantics, the plurality of next hops, the forwarding actions, and the next hop attributes to forwarding information stored by the first network device; and applying, by the first network device and based on the forwarding information, the forwarding actions to network traffic received by the first network device and destined for the network destination when forwarding the network traffic to one or more of the plurality of next hops; and installing, by the first network device and based on the plurality of forwarding semantics, the plurality of next hops, the forwarding actions, and the next hop attributes to forwarding information stored by the first network device; and applying, by the first network device and based on the forwarding information, the forwarding actions to network traffic received by the first network device and destined for the network destination when forwarding the network traffic to one or more of the plurality of next hops; and in response to determining, by the first network device, that the field indicates the attribute is provided for downstream allocation, selecting the second network device to which to forward traffic based on one or more of the plurality of next hops of the second network device and the associated forwarding semantics.