DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-229ATM PNC-DUP (ATM PNC Duplication)
9
unrefresh of those connections that utilize the fau lted component(s) is p erformed.
If the health of the standby PNC improves, a selec tive refresh of connections on
the affected route is performed so that call setup is c onsistent between the active
PNC and the healthy parts of the standb y PNC.
The Standby Refreshed? field on the status pnc screen does
not
refer to the
selective type of refresh. It refers only to a g lobal refresh that is performed when:
■The system is initialized and PNC duplic ation is enabled.
■There has been a spontaneous PNC interchange.
■The standby PNC has been released from b usy-out.
■A system reset of level 2 or higher has taken p lace.
The refreshed field may display yes when in fact the standb y is partially
unrefreshed. An interchange into an inc ompletely refreshed stand by results in
dropped c alls. This can happen when a more sev ere fault occurs on the active
PNC or when reset pnc interchange is used with the override option.
PNC interchanges
PNC spontaneous interchanges occ ur when PNC duplication soft ware
determines that the State of Health (SOH) of the standby PNC is better tha n that
of the active PNC.
■PNC-DUP executes a spontaneous interchange in resp onse to a message
from a PNC component maintenance ob ject indicating that either a fault
has occurred on the ac tive PNC or a fault has been resolved on the
standby PNC.
■The PNC SOH is compared to the standby PNC, and an in terchange
occurs if the state of health of the stand by PNC is now better than that of
the active PNC.
■A corresponding Major or Minor alarm is logged by the reporting MO ,
stimulating an alarm report.
When the resolution of a fault on the standby renders it m ore healthy than a
simultaneously-faulted active PNC, the error messag e indicates the type an d
location of the

improved

component.
Once the interchange c ompletes, the failed c omponent is on the standb y PNC. A
demand interchang e can be requested in the presence or absenc e of standby
PNC faults. The following sequence of actions c an be observed during a
fault-free interchange:
1. The ATM-Expansion Interfaces currently acting as archang els in the EPNs
are deactivated as ind icated by the yellow LEDs goi ng from flashing to on
solid.