Avaya S8700 Series, Maintenance Manual

Page: 964 / 2618

Maintenance-Object Repair Procedures
555-233-143 8-242 Issue 1 May 2002
ATM PNC-DUP
(ATM PNC Duplication)
The PNC-DUP MO tracks the health of the active and standby PNCs, controls
planned and spontaneous interchanges, and manages related functions such as
double call refresh and unrefresh, antithrashing, and so on. The main
responsibility of PNC-DUP is to recover the system to full service in the event of a
fault. In the event of multiple faults, PNC-DUP does its best to maximize service
continuity.
NOTE:
ATM PNC-DUP behaves differently when the system is running the ATM
PNC feature. While not a separate MO, this discussion explains the unique
behavior of PNC-DUP under the ATM PNC feature.
In critical-reliability systems, the following components comprising the
port-network connectivity (PNC), are duplicated:
■
ATM-Expansion Interface (ATM-EI) circuit packs in expansion port
networks (EPNs)
■
Fiber-optic cables connecting the above circuit packs to the ATM Switch
Interface Modules
■
ATM Switch
Although not part of the PNC, Tone-Clock circuit packs are also duplicated in each
EPN. ATM PNC systems can have up to 64 EPNs.
PNC duplication architecture utilizes an active/standby duplication scheme in
which one complete set of PNC components supports call processing, while the
duplicate PNC is held in reserve. All calls on the active PNC are simultaneously
set up, or shadowed, on the standby PNC in order for it to be capable of instantly
assuming active status when necessary, allowing for interchanges without service
disruption (in the case of single faults).
PNC duplication does not introduce any additional types of hardware or hardware
faults, and there are no tests associated with the PNC-DUP MO. Instead, its error
log entries contain useful information about the occurrence and causes of
interchanges in order to facilitate diagnosis of problems, which can then be
addressed by using the documentation for the individual MO involved.
MO’s Name (in
Alarm Log)
Alarm
Level
Initial Command to
Run Full Name of MO
PNC-DUP NA status pnc PNC duplication