1. A method comprising: at a switch unit of a network node, detecting a network disruption event in a network comprising a plurality of interconnected network nodes each of which is configured with a root priority, wherein network nodes in a first set of the network nodes operate as root nodes for ordered network tree paths in the network; retrieving from a database root priority information for each of the network nodes in the network; selecting network nodes for a new set of the network nodes based on the root priority information to operate as new root nodes for new ordered network tree paths upon occurrence of the network disruption event, wherein the new set of network nodes comprises at least one common network node present in the first set; and determining an order of the network nodes in the new set such that the at least one common network node in the new set is maintained in the same order as that in the first set.