This read-only value reports whether the router originating this LSA is an endpoint of one or more fully adjacent virtual links transiting the described area, the V-bit. An admin checks this to identify routers acting as virtual-link endpoints when troubleshooting OSPF virtual links used to connect an area to the backbone. For example, finding this bit on for a router in a non-backbone area confirms that router is terminating a virtual link back to area 0.