This read-write object holds a fifth alternate routing metric for a route entry, with its semantics again defined by the route's clnpRouteProto value and -1 meaning the metric is not used. An admin would see this populated only for a routing protocol reporting five or more distinct per-route metrics, rounding out the set alongside clnpRouteMetric1 through clnpRouteMetric4. For example, a statically configured route with no protocol-specific metrics would leave this field at -1 just like its four sibling metric objects.