A method for determining, at an intermediate network node of a packet-switched communications network, a route to a particular destination in a packet-switched communications network, comprising the steps of: receiving, a plurality of reported costs from a corresponding plurality of neighboring nodes that are linked to the intermediate network node, wherein a reported cost from a corresponding neighboring node is a measure of cost for transmitting data packets to the particular destination node in the network from the corresponding neighboring node; determining a plurality of total costs for the corresponding plurality of neighboring nodes, wherein a total cost for a corresponding neighboring node is a sum of a measure of cost for transmitting data packets to the corresponding neighboring node and the reported cost from the corresponding neighboring node, determining a route to the particular destination node by selecting a neighboring node of the plurality of neighboring nodes, which selected neighboring node has a lowest total cost; determining a feasible successor set of zero or more neighboring nodes of the plurality of neighboring nodes, wherein each neighboring node in the feasible successor set has a corresponding reported cost that is less than the total cost of the selected neighboring node, whereby the neighboring node in the feasible successor set provides a loop free alternative path to the particular destination node, and the feasible successor set excludes the selected neighboring node; determining successor data based on the feasible successor set, the successor data indicating at least whether the feasible successor set has at least one member; and sending, to at least one of the plurality of neighboring nodes, routing protocol control plane messages that include the successor data, to enable the at least one neighboring node to determine whether the intermediate network node should be queried to determine an alternate route to the particular destination node when a specific route to the particular destination node from the at least one neighboring node in the network is lost. receiving, a plurality of reported costs from a corresponding plurality of neighboring nodes that are linked to the intermediate network node, wherein a reported cost from a corresponding neighboring node is a measure of cost for transmitting data packets to the particular destination node in the network from the corresponding neighboring node; determining a plurality of total costs for the corresponding plurality of neighboring nodes, wherein a total cost for a corresponding neighboring node is a sum of a measure of cost for transmitting data packets to the corresponding neighboring node and the reported cost from the corresponding neighboring node, determining a route to the particular destination node by selecting a neighboring node of the plurality of neighboring nodes, which selected neighboring node has a lowest total cost; determining a feasible successor set of zero or more neighboring nodes of the plurality of neighboring nodes, wherein each neighboring node in the feasible successor set has a corresponding reported cost that is less than the total cost of the selected neighboring node, whereby the neighboring node in the feasible successor set provides a loop free alternative path to the particular destination node, and the feasible successor set excludes the selected neighboring node; each neighboring node in the feasible successor set has a corresponding reported cost that is less than the total cost of the selected neighboring node, whereby the neighboring node in the feasible successor set provides a loop free alternative path to the particular destination node, and the feasible successor set excludes the selected neighboring node; determining successor data based on the feasible successor set, the successor data indicating at least whether the feasible successor set has at least one member; and sending, to at least one of the plurality of neighboring nodes, routing protocol control plane messages that include the successor data, to enable the at least one neighboring node to determine whether the intermediate network node should be queried to determine an alternate route to the particular destination node when a specific route to the particular destination node from the at least one neighboring node in the network is lost.