This read-write object holds an alternate routing metric for a route entry, again with semantics defined by the route's clnpRouteProto value and a value of -1 meaning it is unused. An admin uses this alongside clnpRouteMetric1 when a routing protocol reports multiple distinct metrics, such as separate cost and delay figures, for the same route. For example, a protocol that ranks routes by both a primary cost and a secondary tie-breaking value would populate this field with that secondary figure.