This INTEGER, from 1 to 4294967, is the reference bandwidth OSPF uses when auto-calculating the default cost metric for interfaces. Raising this value matters once network links exceed the traditional 100 Mbps OSPF assumption, since otherwise faster links all get the same minimum-cost metric and lose meaningful cost differentiation. An admin who has upgraded core links to 10 Gbps would raise this reference bandwidth so OSPF can still distinguish a 10 Gbps link's cost from a 1 Gbps link's.