Avaya S8700 Maintenance Manual page 350

Maintenance Object Repair Procedure
A correctly designed network has no loops, and each piece of equipment in the
network is supplied by a clock with an equal or lower stratum number. (For
example, the inputs to a Stratum-3 clock should never be from a Stratum-4
device.)
!
CAUTION:
Synchronization administration changes should never be done without
consulting the network's overall synchronization plan. If you suspect that
synchronization administration changes are needed, follow normal
escalation procedures.
Synchronization Switches away from
Current Timing Reference
Synchronization will switch away from a DS1 reference (primary or secondary) if
the current DS1 reference is not providing a valid timing signal. The other DS1
reference will be used if one is administered and providing a valid timing signal.
Otherwise, the local oscillator of the Tone-Clock circuit pack in the same port
network as the DS1 reference will be used. The following conditions will cause a
synchronization switch:
The current DS1 reference is not inserted (that is, list configuration
board UUCSS shows "no board").
The current DS1 reference has a loss of signal error (DS1-BD and
UDS1-BD error type 1281), a blue alarm error (DS1-BD and UDS1-BD
error type 1793), a red alarm error (DS1-BD and UDS1-BD error type
2049), or a hyperactive angel error (DS1-BD and UDS1-BD error type
1538). A corresponding alarm log entry is not required.
DS1 and UDS1 circuit packs can be administered with slips detection
enabled via the Slip Detection? field set to a y (see the add ds1, change
ds1, and display ds1 commands). When over half of the DS1 and UDS1
circuit packs administered as slip enabled are experiencing slips, and the
primary or secondary synchronization reference is the current
synchronization reference, synchronization will try the other administered
synchronization reference if the other administered reference does not
have the previous two conditions. The list measurements ds1-log
command can be used to get an historical perspective of DS1 facility
operation.
The following conditions will cause a switch to the other DS1 reference if one
exists and the other DS1 reference is more healthy:
The current DS1 reference has a misframe error (DS1-BD error type 3329
to 3345 or UDS1-BD error type 3585-3601). A corresponding alarm log
entry is not required.
The current DS1 reference has a slip alarm (DS1-BD and UDS1-BD error
type 3073 to 3160). A corresponding alarm log entry is required.
If the previous conditions are repaired and no longer apply, synchronization will
switch back to the primary reference.
8-1046 Issue 1 May 2002 555-233-142