The value of true signifies that the MAC addresses received
from this partner in the MAC address list in its capabilities
exchange message are the only MAC addresses reachable by
that partner. `False' indicates that other MAC addresses may
be reachable. `False' should be returned before a Capabilities
Exchange message is received, if one is never received, or if
one is received without a MAC Address Exclusivity CV.
If an implementation chooses to keep ciscoDlswTConnOperEntrys in
the `disconnected' state, this value should remain unchanged.