This read-write integer, from 1 to 65534, sets the OSPF cost of sending a packet on this interface, expressed in the link state metric and advertised in the router's router links advertisement. An administrator assigns a lower cost to preferred, higher-bandwidth links so OSPF favors them in path selection, and a higher cost to less desirable backup paths. For example, giving a slow backup WAN link a much higher metric than the primary link ensures OSPF only routes traffic over the backup when the primary is unavailable.