14.5.8. Multisite emergency calls via centralized SIP trunk 
It is possible to install SIP trunks only at the main site and route all calls from
the
branch offices through the main sites SIP trunks. In order to route emergency calls
to the
correct PSAP, the SIP carrier must know the origin of the emergency call.
Some SIP providers (e.g.Vodafone) require to register at least one SIP trunk per branch
office. This allows the carrier to determine the origin of the emergency calls.
OpenScape 4000 must route emergency calls originating in branch offices to the SIP
trunk
assigned to the branch office.
The OpenScape SBC solution is used to connect to the SIP carrier, which allows to
administrate multiple SIP trunks to the carrier, e.g. one trunk per branch office.
These native SIP trunks are linked to core ports at the SIP interface towards the
OpenScape
4000 SIP Gateways.
Example:
SIP trunk 1 is assigned to branch office A. SIP trunk 2 is assigned to branch office
B.
Core port 50000 of the SBC is linked to Central Office trunk 1. Core port 50001 of
the SBC is
linked to Central Office trunk 2.
OpenScape 4000 routes emergency calls originating in branch office A to the SBC core
port
50000. OpenScape 4000 routes emergency calls originating in branch office B to the
SBC core
port 50001.
OpenScape 4000 with its LCR Routing capabilities provides this functionality.
The corresponding core ports need to be set in AMO GKREG. See an example below.
ADD-GKREG:GWNO=99,GWATTR=EXTGW&HG3550V2&SIP,GWIPADDR=10.140.102.208, GWDIRNO=701,DIPLNUM=0,DPLN=0,LAUTH=1,INFO="TRUNK_MULTI", SECLEVEL=TRADITIO,PORT=50000;
ADD-GKREG:GWNO=100,GWATTR=EXTGW&HG3550V2&SIP,GWIPADDR=10.140.102.208, GWDIRNO=702,DIPLNUM=0,DPLN=0,LAUTH=1,INFO="TRUNK_MULTI", SECLEVEL=TRADITIO,PORT=50001;