A data packet routing apparatus comprising: one or more processors; a network interface communicatively coupled to the one or more processors and configured to receive one or more packet flows from a network; a computer readable medium comprising one or more sequences of instructions which, when executed by the one or more processors, cause the one or more processors to perform the steps of: receiving, from a notifying node in the network, a notification identifying the notifying node and a plurality of network components (e.g. 200/214) through which the notifying node can be reached, wherein the network components are nodes or links, the notification specifying for each one of the network components (e.g. 200) a respective repair address (B p) to be used for sending packets to the notifying node not via the respective network component; deriving, from the notification, the repair addresses for use in the event of non-availability of the respective network components identified in the notification; and constructing a repair path to each repair address (e.g. 228, 222, 226, 206), each repair path arranged for sending packets to the notifying node, the repair path not including the respective network component with which the repair address is associated. one or more processors; a network interface communicatively coupled to the one or more processors and configured to receive one or more packet flows from a network; a computer readable medium comprising one or more sequences of instructions which, when executed by the one or more processors, cause the one or more processors to perform the steps of: receiving, from a notifying node in the network, a notification identifying the notifying node and a plurality of network components (e.g. 200/214) through which the notifying node can be reached, wherein the network components are nodes or links, the notification specifying for each one of the network components (e.g. 200) a respective repair address (B p) to be used for sending packets to the notifying node not via the respective network component; deriving, from the notification, the repair addresses for use in the event of non-availability of the respective network components identified in the notification; and constructing a repair path to each repair address (e.g. 228, 222, 226, 206), each repair path arranged for sending packets to the notifying node, the repair path not including the respective network component with which the repair address is associated. receiving, from a notifying node in the network, a notification identifying the notifying node and a plurality of network components (e.g. 200/214) through which the notifying node can be reached, wherein the network components are nodes or links, the notification specifying for each one of the network components (e.g. 200) a respective repair address (B p) to be used for sending packets to the notifying node not via the respective network component; deriving, from the notification, the repair addresses for use in the event of non-availability of the respective network components identified in the notification; and constructing a repair path to each repair address (e.g. 228, 222, 226, 206), each repair path arranged for sending packets to the notifying node, the repair path not including the respective network component with which the repair address is associated.