This read-write object holds the primary routing metric for a given route entry, with its actual meaning determined by whichever routing protocol is named in that route's clnpRouteProto value. An admin configuring or reviewing a static route sets or reads this to compare relative route preference, understanding that a value of -1 specifically means this metric is not used for that entry. For example, a route learned via a distance-vector-style protocol might use this field to hold a hop count, while a statically configured route with no meaningful metric would leave it set to -1.