DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Object Repair Procedures
9-787EXP-INTF (Expansion Interface Circuit Pack)
9
In a system that is configured with PNC duplication active, taking an EI out of
service that is on the active PNC will, if all other thing s on the active and stand by
PNC are equal (i.e. both PNCs are equally healthy, the standby PNC is not busied
out, the PNC is not locked by software), result in a PNC interchang e.
Survivable Remote EPN
The Survivable Remote EPN (SREPN) feature allows a DEFINITY R6r EPN (either
MCC or SCC) to provide service to the c ustomer when:
■The fiber (or T1/E1 Expansion Interface link to the main R6r processor)
fails or is severed
■The R6r processor or center stage fails.
NOTE:
This feature is viewed as a “disaster rec overy operation” c apability rather
than as an additional reliabil ity option.
The SREPN re quir es rem ote EPN cab inet to pr ovid e pro ces sor ( SPE) cap abi liti es
to the EPN in the event of a failure. A logic switch c ircuit pack (TN2301) located
in the SRPPN detects when the link to the R6r is down and switches to a link from
the local SRPPN (TN790-based processor). When the links to the R6r are
restored and verified to b e stable, the logic switch is

manually reset

, and the
EPN is reconnected to the links from the R6r.
NOTE:
The SREPN feature is not available when an ATM-PNC/EI circuit pack is
used to replace the TN570 EI circuit p ack in a direct-c onnect configuratio n,
or an ATM Switch is providing the Center Stage (PNC) connecti vity.
NOTE:
If you suspect a problem with the TN790B-b ased R6si SRPPN use the R6si
maintenance documentati on supplied with the SREPN feature to resolve
any alarms/errors associated with the SRPPN carrier.
SREPN Feature Active
!WARNING:

All calls within the SREPN are terminated when the SREPN feature is

activated, and the

R6si

SRPPN take s co ntrol of the SREPN.

The SREPN feature is activated when the maintenanc e circuit pac k (TN775C or
later and located in th e SREPN) detects a problem with the SREPN’s EI (TN570B)
LAPD link to its counterpart in the R6r PPN. The TN775C maintenance circuit
pack notifies the co-loc ated SRPPN of the problem, and the TN2301 SRSwitch
circuit pack in t he SRPPN carrier switches the EI LAPD link connection from the