This notification is generated when the pwOperStatus
object for one or more contiguous entries in the pwTable are
about to enter the down(2) or lowerLayerDown(6) state from
any other state, except for transition from the
notPresent(5) state.  For the purpose of deciding when
these notifications occur, the lowerLayerDown(6) state
and the down(2) state are considered to be equivalent;
i.e., there is no notification on transition from
lowerLayerDown(6) into down(2), and there is a trap on
transition from any other state except down(2) (and
notPresent) into lowerLayerDown(6).
          
The included values of pwOperStatus MUST each be equal to
down(2) or lowerLayerDown(6).  The two instances of
pwOperStatus in this notification indicate the range of
indexes that are affected.  Note that all the indexes of
the two ends of the range can be derived from the
instance identifiers of these two objects.  For cases
where a contiguous range of cross-connects have
transitioned into the down(2) and lowerLayerDown(6) states
at roughly the same time, the device SHOULD issue a single
notification for each range of contiguous indexes in an
effort to minimize the emission of a large number of
notifications.  If a notification has to be issued for
just a single cross-connect entry, then the instance
identifier (and values) of the two pwOperStatus objects
MUST be identical.

This notification is generated when the pwOperStatus
object for one or more contiguous entries in the pwTable are
about to enter the up(1) state from some other state
          
except the notPresent(5) state and given that the pwDown
notification been issued for these entries.  The included
values of pwOperStatus MUST both be set equal to this
new state (i.e., up(1)).  The two instances of pwOperStatus
in this notification indicate the range of indexes that
are affected.  Note that all the indexes of the two ends
of the range can be derived from the instance identifiers
of these two objects.  For cases where a contiguous range
of cross-connects have transitioned into the up(1) state
at roughly the same time, the device SHOULD issue a single
notification for each range of contiguous indexes in an
effort to minimize the emission of a large number of
notifications.  If a notification has to be issued for
just a single cross-connect entry, then the instance
identifier (and values) of the two pwOperStatus objects
MUST be identical.

This notification is generated when the PW has been
deleted, i.e., when the pwRowStatus has been set to
destroy(6) or the PW has been deleted by a non-MIB
application or due to an auto-discovery process.