This enumerated object, enable or disable, controls whether this virtual interface advertises a default route via RIP. Enabling it turns this interface into a source of last-resort routing information for RIP neighbors downstream, useful at the edge of a network where a simple default suffices instead of the full route table. An admin at the hub of a hub-and-spoke RIP topology would enable this on the interface facing the spokes so those remote routers get a default route instead of a full table.