This is an alternate routing metric for the route, again with meaning set by the protocol identified in aniDevRouteProto, defaulting to -1 when unused. It gives admins a secondary cost value some routing protocols report alongside the primary metric, useful when comparing tie-broken routes to the same destination. For example, a route learned via a protocol that reports two cost dimensions might show aniDevRouteMetric1 as the primary distance and aniDevRouteMetric2 as a secondary value like path reliability, while an unused case simply reads -1.