The routing metric for this route. The
semantics of this metric are determined by the
routing protocol specified in the route's
ipv6RouteProtocol value. When this is unknown
or not relevant to the protocol indicated by
ipv6RouteProtocol, the object value should be
set to its maximum value (4,294,967,295).
This object is obsoleted by
IP-FORWARD-MIB::inetCidrRouteMetric1.