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 Conn ectivity (PNC), are duplicated :
■Expansion Interface (EI) TN570 circuit pac ks in the port networks (PNs)
■Switch Node Interface (SNI) TN573 circuit p acks in switch nodes
■DS1 Converter (DS1C) TN574 circuit packs for remote EPN connectio ns
■Fiber-optic cab les (metallic in certain cases) c onnecting the above c ircuit
packs
■DS1 facilities between the DS1Cs
■Switch Node Clock (SNC) TN572 circuit pac ks
Although not part of the PNC, Tone-Clock circuit p acks are also duplic ated in
each PN. The PNC is available in two different configura tions: direct connec t, in
which each port networ k is connected d irectly by fiber op tic links to each other
PN; and Center Stage Switch (CSS) which utilizes one or two switch nod es to
interconnect the PNs. All systems have one Processor Port Network (PPN). Direct
connect systems can have u p to two Expansion Port Networks (EPNs). CSS
systems with one switch node c an have up to 15 EPNS. CSS systems with two
switch node can have up to 21 EPNS. See the following figures.
PNC duplication architec ture utilizes an active/standb y duplication sc heme, in
which one complete set of PNC c omponents supports c all processing, whil e 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).
The PNC-DUP maintenance object tracks the health of the ac tive and standby
PNCs, controls planned and sp ontaneous interchanges, and manages 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 will do its b est to
maximize service continuity.
PNC duplication does not introd uce any additi onal 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 ord er to facilitate diagnosi s of
problems which c an then be addressed by using the doc umentation 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