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DEFINITY ECS Release 8.2 Maintenance for R8.2csi
555-233-119 Issue 1
April 2000
Maintenance Objects
3-204ATM PNC-DUP (ATM PNC Duplication)
3
Once the interchange completes, the failed component is on the standby PNC. A
demand interchange can be requested in the presence or absence of standby
PNC faults. The following sequence of actions can be observed during a
fault-free interchange:
1. The ATM-Expansion Interfaces currently acting as archangels in the EPNs
are deactivated as indicated by the yellow LEDs going from flashing to on
solid.
2. The PPN ATM-EIs are interchanged, indicated by the new standby ATM-EI
yellow LED off and the new active ATM-EI yellow LED on steady.
3. One by one the EPN ATM-EIs are interchanged as indicated by new
standby ATM-EI yellow LED turning off and the new active ATM-EI yellow
LED flashing (2 seconds on/200 milliseconds off). At this point the
interchange is functionally complete.
Certain conditions may interfere with the normal execution of the interchange:
1. In a faulted spontaneous interchange, it is possible the EPN/EPNs directly
affected by the fault will be the last to interchange.
2. A user directly affected by the single fault instigating a PNC interchange
can experience a momentary voice path outage during the switch.
3. If faults exist on both the standby and active PNC, it is possible to have
some EPNs go out of service while others are returned to service.
In any multifault situation, rely on
status pnc
to determine which is the active
PNC.
PNC duplication informs Timing Synchronization maintenance when a PNC
interchange has been completed and indicates which PNC is active. This causes
Synchronization to audit and ensure that the primary source for synchronization
of Tone-Clocks in each PN is supplied by a path associated with the active PNC.
Antithrashing and PNC interchanges
Following a spontaneous PNC interchange, subsequent PNC interchanges are
prevented for 5 minutes. This condition is indicated by
y
in the
Interchange
Disabled?
field of the
status pnc
screen. After 5 minutes, the antithrashing,
timer expires, interchange decisions are re-enabled, and the field displays
n
.
Should a catastrophic failure occur on the active PNC during the period when the
Interchange Disabled?
field is set to “yes,” there will be no spontaneous
PNC interchange.