Demand test descriptions and error codes - Avaya Support

3. If faults exist on both the standby and active PNC, it is possible to have some PNs go out
of service while others are returned to service.
4. The new standby SNIs amber LED my not be off due to a fault in the line of communication
path to the standby SNIs. In a multi-fault interchange, LEDs on the new active SNIs may
not be on for the same reason.
In any multi-fault situation, use 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
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 y in the Interchange Disabled field of the status PNC
screen. After 5 minutes, the anti-thrashing, timer expires, interchange decisions are re-enabled,
and the field entry is n.
Note:
Note: Should a catastrophic failure occur on the active PNC during the period when
Interchange Disabled? is set to y, there will be no spontaneous PNC
interchange.
Demand PNC interchanges also invoke anti-thrashing, but only for a period of 30 seconds.
During anti-thrashing 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:
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:
764 Maintenance Alarms for Communication Manager, Media Gateways and Servers