A method is disclosed for constructing a repair path for multicast data around a non-available component in a data communications network having as components nodes and links therebetween. The method comprises the step performed at a repairing node, of receiving from a notifying node in a network, a notification identifying the notifying node and components through which the notifying node can be reached. The method further comprises the steps of deriving, from the notification, a network repair address for use in the event of non-availability of a component identified in the notification; and constructing a repair path for multicast data for the repair address.