This is the metric value for reaching the specified destination over this circuit, following the ManualOrAutomatic behavior. It is the narrow routing cost applied to this specific IP reachability entry, functioning like ciiCircLevelMetric but for a manually configured or redistributed prefix rather than a directly connected circuit, directly shaping whether SPF favors this route over a competing path. For example, assigning a deliberately high metric like 63, the narrow-metric maximum, to a redistributed backup default route ensures it is only ever used if every genuinely internal IS-IS path to that destination becomes unavailable.