DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-1304PNC-DUP (PNC Duplication)
9
Antithrashing and PNC Interchanges
Following a spontaneous PNC interchange, sub sequent PNC interchanges are
prevented for 5 minutes. This conditio n is indicated by a "yes" in the Interchange
Disabled? field of the status pnc screen. After 5 minutes, the antithrashing, ti mer
expires, interchange d ecisions are re-enabled, and the field displays ‘‘no.’’
Should a catastrophic failure oc cur on the active PNC during the period when
"Interchange Disabled?" 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 second s. During antithrashing mod e, demand interchanges are also
prevented unless the override o ption is specified. Us e of this option will cause a
service 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
following repair proc edures. This can happen, for examp le, when a slave
tone/clock circuit pack experi ences a l oss of signal and switches to receive
timing from the standby EI. In this case TDM-CLK 2305 error will b e logged,
and the clock p roblem should be ad dressed first, if possib le.
To repair PNC components in a duplicated PNC proceed as follows:
1. Most repairs will involve fixing a sing le fault on the standby PNC. Use set
pnc lock or busy-out pnc to prevent an interchange int o the PNC being
repaired.
2. If a faulty component exists on the currently ac tive PNC, the standby PNC
is more severely faulted. Normally the standb y PNC will be fully repaired
first since it is the most severely impaired . To repair the active PNC,
request an interchange via the reset pnc interchange override-and-lock
command. The
override-and-lock
option ensures that no subsequent
interchange will occ ur during the repair of the stand by PNC. The demand
interchange may not be nec essary if the following cond itions drive a
spontaneous interchange:
■The anti-thrashing period from the last interc hange has expired.
■The global refresh from releasing the standby PNC has completed.
The standby PNC SOH is better than the active.
3. At this point, the faulty comp onent will be on the standby PNC, and t he
PNCs are locked in their current active /standby state. Busy-out the PNC.
Then fault isolation and component testin g procedures for the ind ividual
PNC components can be used just as for a simplex PNC. Replacement of
components will not disrup t operation of the active PNC.