When an interface gets a valid Neighbor Advertisement message the node behavior depends whether the target address is tentative or atches a unicast or anycast address assigned to the interface.
If the target address is assigned to the receiving interface, the solicitation is processed as described in [DISCOVERY].
If the target address is tentative, the tentative address is not unique.
A tentative address that is determined to be a duplicate as described above, MUST NOT be assigned to an interface and the node SHOULD log a system management error. If the address is a link-local address formed from an interface identifier, the interface SHOULD be disabled.
