DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126
Issue 4
June 1999
Maintenance Object Repair Procedures
9-1294PNC-DUP (PNC Duplication)
9
PNC-DUP (PNC Duplication)
In systems with the Critical Reliability option, the following components, which
together comprise the Port Network Connectivity (PNC), are duplicated:
■ Expansion Interface (EI) TN570 circuit packs in the port networks (PNs)
■ Switch Node Interface (SNI) TN573 circuit packs in switch nodes
■ DS1 Converter (DS1C) TN574 circuit packs for remote EPN connections
■ Fiber-optic cables (metallic in certain cases) connecting the above circuit
packs
■ DS1 facilities between the DS1Cs
■ Switch Node Clock (SNC) TN572 circuit packs
Although not part of the PNC, Tone-Clock circuit packs are also duplicated in
each PN. The PNC is available in two different configurations: direct connect, in
which each port network is connected directly by fiber optic links to each other
PN; and Center Stage Switch (CSS) which utilizes one or two switch nodes to
interconnect the PNs. All systems have one Processor Port Network (PPN). Direct
connect systems can have up to two Expansion Port Networks (EPNs). CSS
systems with one switch node can have up to 15 EPNS. CSS systems with two
switch node can have up to 21 EPNS. See the following figures.
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).
The PNC-DUP maintenance object 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 will do its best to
maximize service continuity.
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, it’s error log entries are used to log 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 maintenance object involved.
MO Name (in
Alarm Log)
Alarm
Level
Initial Command to
Run Full Name of MO
PNC-DUP NA status pnc PNC duplication
