PNC-DUP (PNC Duplication)
Issue 1 May 2002
8-1293
555-233-143
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 will
cause Synchronization to audit and insure 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 a yes in the
Interchange Disabled?
field of the Status PNC form. After 5 minutes, the
antithrashing, timer expires, interchange decisions are re-enabled, and the field
displays no.
NOTE:
Should a catastrophic failure occur 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
seconds. During antithrashing mode, demand interchanges are also prevented
unless the override option is specified. Use 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 circuit switched data may be affected by the following
repair procedures. This can happen, for example, when a slave tone/clock
circuit pack experiences a loss of signal and switches to receive timing from
the standby EI. In this case TDM-CLK 2305 error will be logged, and the
clock problem should be addressed first, if possible.
To repair PNC components in a duplicated PNC proceed as follows:
1. Most repairs will involve fixing a single fault on the standby PNC. Use set
pnc lock or busy-out pnc to prevent an interchange into the PNC being
repaired.
2. If a faulty component exists on the currently active PNC, the standby PNC
is more severely faulted. Normally the standby 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
Содержание S8700 Series
Страница 50: ...Maintenance Architecture 555 233 143 1 26 Issue 1 May 2002 ...
Страница 74: ...Initialization and Recovery 555 233 143 3 12 Issue 1 May 2002 ...
Страница 186: ...Alarms Errors and Troubleshooting 555 233 143 4 112 Issue 1 May 2002 ...
Страница 232: ...Additional Maintenance Procedures 555 233 143 5 46 Issue 1 May 2002 ...
Страница 635: ...status psa Issue 1 May 2002 7 379 555 233 143 status psa See status tti on page 7 406 ...
Страница 722: ...Maintenance Commands 555 233 143 7 466 Issue 1 May 2002 ...
Страница 1121: ...CARR POW Carrier Power Supply Issue 1 May 2002 8 399 555 233 143 Figure 8 19 Power Distribution Unit J58890CH 1 ...
Страница 1447: ...E DIG RES TN800 reserve slot Issue 1 May 2002 8 725 555 233 143 E DIG RES TN800 reserve slot See ASAI RES ...
Страница 1735: ...LGATE AJ Issue 1 May 2002 8 1013 555 233 143 LGATE AJ See BRI SET LGATE BD See BRI BD LGATE PT See BRI PT ...
Страница 1846: ...Maintenance Object Repair Procedures 555 233 143 8 1124 Issue 1 May 2002 Figure 8 62 TN787 MMI MULTIMEDIA INTERFACE CIRCUIT PACK ...