This attribute indicates the minimum DPN delay metric to the
destination RID. The delay metric associated with a path is
computed by the routing system by translating the smallest
delayMetric calculated for the destination. A path with a lower
metric value is preferable to one with a higher value as it is
associated with lower delay facilities. The metric displayed is that
of the best path to the destination. This metric is advertised to
neighbor RMs and Passports in a different RID subnet.
A metric value of 255 means the RID is unreachable in the delay
class of service. A value of 0 indicates that no cost is associated
with the path to the destination. This would be the case for the local
node's RID. A metric value of 252 indicates that the destination
RID is that of a Network Module (NM).