If this object is set to true, the reachability of the next-hops of routes in this address-family are checked. If this object is set to false, the next-hops if routes in this address-families are always considered to be reachable. This attribute only applies to address- families with SAFI 128 (labeled-vpn-unicast). For all other address- families this attributes is meaningless and attempting to set the attribute will result in an error.