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 c ompletes, the failed c omponent is on the standby PNC. A
demand interchang e can be requested in the presence or absence of s tandby
PNC faults. The following sequence of actions c an be observed d uring a
fault-free interchange:
1. The ATM-Expansion Interfaces currently acting as archang els in the EPNs
are deactivated as ind icated by the yellow LEDs going from flashing to on
solid.
2. The PPN ATM-EIs are intercha nged, 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 b y new
standby ATM-EI yellow LED turning off and the new active ATM-EI yellow
LED flashing (2 seconds on/200 millisec onds off). At this point the
interchange is functionally complete.
Certain conditions may interfe re with the normal execution of the interchang e:
1. In a faulted spontaneous interchan ge, it is possible the EPN/EPNs directly
affected by the fault will b e the last to interchange.
2. A user directly affected by the single fault instigating a PNC interchange
can experience a momentar y voice path outage d uring the switch.
3. If faults exist on both the standb y and active PNC, it is possible to have
some EPNs go out of service while others are returned to servic e.
In any multifault situation, rely on status pnc to determine whic h is the active
PNC.
PNC duplication informs Timing Sync hronization maintenance when a PNC
interchange has been c ompleted and indi cates 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 p ath associated with the ac tive PNC.
Antithrashing and PNC interchanges
Following a spontaneous PNC interchange, sub sequent PNC interchanges are
prevented for 5 minutes. This condi tion is indicated by y in the Interchange
Disabled? field of the status pnc screen. After 5 minutes, the antithras hing,
timer expires, interchange d ecisions are re-enabled, and the field displays n.

Should a catastrophic failure oc cur on the active PNC during the period when the

Interchange Disabled?

field is set to “yes,” the re will be no spontaneous

PNC interchange.