DEFINITY ECS Release 8.2 Maintenance for R8.2csi
555-233-119 Issue 1
April 2000
Maintenance Objects
3-203ATM PNC-DUP (ATM PNC Duplication)
3
Refresh and unrefresh of the standby PNC
In a fully-functional PNC with healthy standby and active sides, the standb y PNC
has a complete set of call c onnections correspond ing to those in the active PNC.
If, however, the state of health of the standby PNC d egrades, a selective
unrefresh of those connections that utilize the fau lted component(s) is p erformed.
If the health of the standby PNC improves, a sele ctive refresh of connections on
the affected route is performed so that call setup is consiste nt 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 displ ay yes when in fact the standby is p artially
unrefreshed. An interchange into an inc ompletely refreshed standb y results in
dropped c alls. This can happen when a more severe fault oc curs 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 software
determines that the State of Health (SOH) of the standby PNC is b etter than that
of the active PNC.
■PNC-DUP executes a spontaneous interchange in response to a message
from a PNC component maintenance ob ject indicating that e ither 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 and
location of the

improved

component.