This is the primary routing metric for the entry, whose meaning, such as hop count or path cost, depends on which routing protocol, per ipForwardProto, produced the route, and it is -1 if unused. Admins compare this value across competing routes to a destination to understand which one the routing protocol considers best, though the units differ by protocol, for instance RIP metrics are hop counts while OSPF metrics are path cost. For example, a RIP-learned route might show this value as 3, meaning it is three hops away, while a statically configured route not using a metric would show -1.