A source network node performs routing path selection in a communications network by steps that include acquiring a dynamically changing metric value of at least one of a plurality of data routing paths extending from the source network node to a destination network node to which data is to be routed. A determination is made as to which of the data routing paths the data is to be routed on the basis of the acquired dynamically changing metric value of the at least one data routing path in order to satisfy at least one predetermined routing criterion. Routing of the data from the source network node to the destination node is then controlled to be performed over the determined data routing paths.