DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-230ATM PNC-DUP (ATM PNC Duplication)
9
2. The PPN ATM-EIs are interchanged, indic ated by the new standb y 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 millisec onds off). At this point the
interchange is functionally c omplete.
Certain conditions may interfere with the normal execution of the interchang e:
1. In a faulted spontaneous interchang e, 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 possib le 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 Synchroniza tion maintenance when a PNC
interchange has been c ompleted and ind icates 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 b y y in the Interchange
Disabled? field of the status pnc screen. After 5 minutes, the antithrashin g,
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,” there will be no spontaneous

PNC interchange.

Demand PNC interchanges also invoke anti-thrashing , but only for a period of 30
seconds. During antithras hing mode, demand interchanges are also prevented
unless the override option is sp ecified.
!CAUTION:

Use of this option may cause a servic e disruption.

Repairs on the standby PNC components
!CAUTION:

If there is a TDM-CLK alarm, system timing may be routed through part of

the standby PNC, and circ uit switched data may b e affected by the