Outgoing Route Selection

If the local MSC determines that the called subscriber is served by another MSC through the core procedure of number analysis, it needs to select an available circuit for routing the call to another MSC. Outgoing route selection refers to a process of routing the call out of the local MSC and obtaining the outgoing office direction and DPC. Figure 1 shows the flowchart of outgoing route selection.

Figure 1 Flowchart

 

NOTE:
 

The mandatory tables for querying are highlighted by solid-line frames and the optional tables are highlighted by dotted-line frames.

In the table querying procedure, pay attention to the following items:

• Identifying the call as incoming trunk call or MOC does not occur in parallel with querying the Call Prefix table. In practice, the call type is not known until after the MSC server queries the Trunk Group table (Office Direction table) and the 2G LAI or GCI Information table (3G LAI or SAI Information table) to obtain the call source name. In the flowchart above, the sequence of actions is altered to increase your understanding of which inputs are required for outgoing route selection.
• For a BICC incoming call, the MSOFTX3000 queries the Office Direction table for the call source name. For the incoming calls of other types, such as ISUP, TUP, PRA, and SIP, the MSOFTX3000 queries the Trunk Group table for the call source name.
• For a SIP call, the trunk circuit is not involved and thus the MSOFTX3000 need not query the Trunk Circuit table in the outgoing procedure.
• The Trunk Group table or Office Direction table is queried twice during the outgoing route selection procedure. For the first time, the Trunk Group table or Office Direction table is queried to obtain the call source name; for the second time, the Trunk Group table is queried to obtain the trunk circuit and the Office Direction table is queried to obtain the DSP.
• The BICC SCTP Link table is queried only when the trunk office direction is BICC.

Table Description

Table	Command	Input Parameter	Output Parameter	Function Description
Trunk Group table (involved in the incoming call procedure)	ADD N7TG ADD BICCTG ADD SIPTG ADD PRATG	Trunk group name	Call source name	This table is used to configure trunk groups. For a BICC incoming call, the MSOFTX3000 queries the Trunk Group table and then the Office Direction table for the call source name, which is used for querying the Call Source table subsequently. Based on the trunk group name, the MSOFTX3000 queries the Trunk Group table for the call source name, which is used for querying the Call Source table subsequently. NOTE:  ADD N7TG is used to configure SS7 trunk groups. ADD BICCTGis used to configure BICC trunk groups. ADD PRATGis used to configure PRA trunk groups. ADD SIPTGis used to configure SIP trunk groups.
2G LAI or GCI Information table (3G LAI or SAI Information table)	ADD LAIGCI ADD LAISAI	Global cell ID	Call source name	This table is used to configure the location area or cell where the subscriber resides. ADD LAIGCIis applicable to the 2G network. ADD LAIGCIis applicable to the 3G network. Based on the global cell ID, the MSOFTX3000 queries the 2G LAI or GCI Information table or 3G LAI or SAI Information table for the call source name, which is used for querying the Call Source table subsequently.
Call Source table	ADD CALLSRC	Call source name	Route selection source name DN set	Based on the call source name, the MSOFTX3000 queries the Call Source table for the route selection source name and DN set, which are used for the subsequent number analysis and outgoing route selection.
Call Prefix table	ADD CNACLD	Call prefix DN set	Route selection source name Service attribute Called number type	Based on the call prefix and DN set, the MSOFTX3000 queries the Call Prefix table for the route selection source name, service attribute, and called number type, which are used for the subsequent outgoing route selection.
Route Analysis table	ADD RTANA	Route selection name Route selection source name	Route name	Based on the route selection name and route selection source name, the MSOFTX3000 queries the Route Analysis table for the route name, which is used for querying the Route table subsequently.
Route table	ADD RT	Route name	Sub-route name	Based on the route name, the MSOFTX3000 queries the Route table for the subroute name, which is used for querying the Sub-route table and Trunk Group table subsequently.
Sub-route table	ADD SRT	Sub-route name	Office direction name Trunk group selection mode	Based on the sub-route name, the MSOFTX3000 queries the Sub-route table for the office direction name and the trunk group selection mode, which is used for querying the Office Direction table subsequently. You can configure multiple subroute names for route reselection. For a BICC call, the office direction name is also used to query the BICC SCTP Link table (ADD BICCSCTPLNK) to determine an SCTP link and the corresponding IP address and port number of the peer office. For a SIP call, the office direction name is also used to query the SIP Office Media Gateway table (ADD OFCMGW) for the MGW name.
Trunk Group table (involved in the outgoing call procedure)	ADD N7TG ADD BICCTG ADD SIPTG ADD PRATG	Sub-route name	Trunk group name Circuit type MGW name Circuit selection mode	Based on the subroute name, the MSOFTX3000 queries the Trunk Group table for the trunk group name and MGW name, which are used for querying the Trunk Circuit table subsequently. The MSOFTX3000 queries the SIP Trunk Group table to obtain the local IP address, SIP_URL, and local port number, which are used for outgoing route selection. The MSOFTX3000 queries the BICC Trunk Group table to obtain the bearer setup direction, tunnel mode, and MGW name, which are used for outgoing route selection. The MSOFTX3000 queries the PRA Trunk Group table to obtain the MGW name, PRA link name, and default calling number, which are used for outgoing route selection. NOTE:  ADD N7TG is used to configure SS7 trunk groups. ADD BICCTGis used to configure BICC trunk groups. ADD PRATGis used to configure PRA trunk groups. ADD SIPTGis used to configure SIP trunk groups.
Trunk Circuit table	ADD N7TKC ADD PRATKC ADD BICCCICMDU	Trunk group name Office direction name	Start CIC End CIC Start circuit termination ID End circuit termination ID	For an ISUP, TUP, or PRA call, the MSOFTX3000 queries the Trunk Circuit table based on the trunk group name for the CICs and circuit termination IDs. For a BICC call, the MSOFTX3000 queries the Trunk Circuit table based on the trunk group name for the CICs.
Office Direction table	ADD OFC	Office direction name	DSP	Based on the office direction name, the MSOFTX3000 queries the Office Direction table for the DSP, peer office level, and signaling category, which are used for subsequent outgoing route selection.
BICC SCTP Link table	ADD BICCSCTPLNK	Office direction name	Link name Peer IP address Peer port number	Based on the office direction name, the MSOFTX3000 queries the BICC SCTP Link table for the BICC SCTP link name, peer IP address, and peer port number.