10.2.9.3. Payload Survivability in OpenScape 4000 Networks 
Payload survivability is destination-oriented and is restricted to
one OpenScape 4000 system. If other systems are connected to the
OpenScape 4000 via ECMAV2 trunks (closed numbering), the networking LCR
(NWLCR) must be extended. Otherwise, AP subscribers cannot access the
relevant network subscribers when payload survivability is active.
The procedure followed for payload survivability between a local subscriber
and a CO/tie trunk circuit is route-specific.
If the call comes in via the CO/tie trunk circuit, a trunk call is
established between the source group into which the call comes and the
source group to which the subscriber belongs.
If, on the other hand, the OpenScape 4000 subscriber establishes the
call, the call is routed out of the system via the CO using LCR. A tie
trunk from the central system cannot be used in this case.
Figure 32 “Payload survivability and networking - normal route A calls B or B calls A”,
Figure 33 “Payload survivability and networking - survivability route A calls B”
and Figure 34 “Payload survivability and networking - survivability route B calls A”
show the different routes.
To handle call A -> B with payload survivability (Figure 33 “Payload survivability and networking - survivability route A calls B”),
an extension must be added to the NWLCR of system 1 for the route to
DESTNO 2. This extension contains an overflow entry to the local CO of
AP 17 (trunk group 17), which ensures that routing to destination system
2 takes place via CO in the case of payload survivability.
Figure 197. Payload survivability and networking - normal route A calls B or B calls A
Figure 198. Payload survivability and networking - survivability route A calls B
Figure 199. Payload survivability and networking - survivability route B calls A
NWLCR extension for AP 17 to system 2 with payload survivability (Figure 33 “Payload survivability and networking - survivability route A calls B”)
+--------------------------------------------------------------------------+ | LRTE = 124 NAME = SYSTEM 2 SERVICE = ALL | | TYPE = NWLCR DIDNO-ROUTE = 1 -2 -400 | | SERVICE INFO = | +-------+-----+-----+-----+------+----------+------------+----------+------+ | | | | | | SCHEDULE | CARRIER | | | |LRTGEL |LVAL |TRUNO| LWR| LBER | ABCDEFGH | ZONE | LATTR | LDSRT| +-------+-----+-----+-----+------+----------+------------+----------+------+ | 1 | 1| 24| 1| 1 | ******** | 1 EMPTY | NONE | | | 2 | 1| 17| 17| 17| |******** | 1 EMPTY | NONE | | +-------+-----+-----+-----+------+----------+------------+----------+------+ +-------------------------------------------------------+ | LWR LWRELPOS LWREL PARAMETER | +--------+----------------------------------------------+ | 1 | 1 ECHO 1 | | | 2 END | +--------+----------------------------------------------+ |INFO:STANDARD NWLCR FOR SYSTEM 2 | +-------------------------------------------------------+ +-------------------------------------------------------+ | LWR LWRELPOS LWREL PARAMETER | +--------+----------------------------------------------+ | 17 | 1 OUTPULSE 696400 | | 2 | 1 ECHO 1 | | | 3 NPI ISDN | | | 4 TON NATIONAL | | | 5 END | +--------+----------------------------------------------+ |INFO:OVERFLOW CO FOR SYSTEM 2 (SURVIVABILITY) | +--------+----------------------------------------------+