DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-224ATM PNC-DUP (ATM PNC Duplication)
9
ATM PNC-DUP (ATM PNC Duplication)
The PNC-DUP maintenance object tracks the health of the ac tive and standby
PNCs, controls planned and sp ontaneous interchanges, and m anages related
functions such as doub le 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 b est to
maximize service continuity.
In systems with the Critical Reliability option, the following components, whic h
together comprise the Port Network Conn ectivity (PNC), are duplicated :
■ATM-Expansion Interface (ATM-EI) circuit packs in the port networks (PNs)
■Fiber-optic cab les connecting the ab ove circuit packs t o the ATM Switch
Interface Modules
■ATM Swi tc h
Although not part of the PNC, Tone-Clock circuit p acks are also duplica ted in
each PN. All systems have one Processor Port Network (PPN). ATM PNC systems
can have up to 43 EPNs.
PNC duplication architec ture utilizes an active/standby d uplication scheme i n
which one complete set of PNC c omponents supports c all processing, while the
duplicate PNC is held in reserve. A ll calls on the active PNC are simultaneously
set up, or shadowed, on the stand by PNC in order for it to be cap able of instantly
assuming active status when nec essary, allowing for interchanges without
service disruption (in the c ase of single faults).
PNC duplication does not introd uce any additional typ es 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 occurrenc e and
causes of interchanges in ord er to facilitate diagnosis o f problems, which can
then be addressed by using the doc umentation for the individual maintenanc e
object involved.

PNC-DUP Related Commands

The following commands and their outp ut screens are fully described in Chapter
8.
MO Name (in
Alarm Log) Alarm
Level Initial Command to
Run Full Name of MO
PNC-DUP NA status pnc PNC duplication