Pnc-Dup (Pnc Duplication) - Avaya S8700 Maintenance Manual

PNC-DUP (PNC Duplication)

PNC-DUP (PNC Duplication)
MO's Name (in
Alarm Log)
PNC-DUP
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 PN 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
IP Server Interface (IPSI) TN2312AP 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. Direct connect systems can have up to two PNs. CSS systems with one
switch node can have up to 15 PNs. CSS systems with three switch node can
have up to 44 PNs. 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 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 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, error
log entries are used to log useful information about the occurrence and causes of
interchanges. This is done in order to facilitate diagnosis of problems, which can
then be addressed by using the documentation for the individual MO involved.
555-233-143
Alarm Level Initial Command to Run
NA status pnc
Full Name of MO
PNC duplication
Issue 1 May 2002 8-1283