Avaya 03-300430 User Manual

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Communication Manager Maintenance-Object Repair Procedures
594 Maintenance Procedures for Avaya Communication Manager 3.0, Media Gateways and Servers
 
Antithrashing and PNC Interchanges
Following a spontaneous PNC interchange, subsequent PNC interchanges are prevented for 5 
minutes.  This condition is indicated by y in the Interchange Disabled? field of the status 
pnc
 screen.  After 5 minutes, the antithrashing timer expires, interchange decisions are 
re-enabled, and the field displays n.
Note:
Note:
Should a catastrophic failure occur 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 antithrashing mode, demand interchanges are also prevented unless the override option 
is specified.
!
CAUTION:
CAUTION:
Use of this option may 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 
ATM-EI.  In this case TDM-CLK 2305 error is 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 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 active PNC, this also means that the standby PNC is 
more severely faulted.  Normally, the standby PNC is repaired first, since it is the most 
severely impaired.  
To repair the active PNC (standby is already repaired), enter set pnc unlock, which 
generates a spontaneous interchange.  In a PNC demand interchange with reset pnc 
interchange
 use the override-and-lock qualifier for the active PNC.  The 
override-and-lock option ensures that no subsequent interchange can occur during 
the repair of the standby PNC.  A demand interchange may not be necessary if the following 
conditions drive a spontaneous interchange:
The anti-thrashing period from the last interchange has expired.