A communications network node has a memory storing information about the topology of a network, configuration data comprising attributes of the network, and information about a routing protocol of the network. The memory stores a comparison function derived from a best path definition of the routing protocol. A path finding component of the node computes, for an individual one of the nodes, a routing table specifying which neighbors of the individual node incoming data received at the individual node is to be routed to, where computing the routing table comprises searching for optimal paths between the nodes, using the information about the topology of the network and the configuration data, and using the comparison function to guide the search; and wherein optimal paths between the nodes are optimal with respect to one or more of the attributes.