This read-write Unsigned32 sets the global DVMRP distance metric used to calculate distance vectors, which an interface inherits by default unless its own dvmrpInterfaceMetric has been explicitly modified. An admin adjusts this global default to influence DVMRP's reverse-path-forwarding route selection across all interfaces that haven't been given a per-interface override. For example, raising the default metric from 1 would make this router's DVMRP-advertised routes look less attractive to neighbors unless individual interfaces override it.