Cisco Cisco ASR 5000
3G-2G Location Change Reporting
How it Works ▀
SGSN Administration Guide, StarOS Release 18 ▄
How it Works
When the Location Change Reporting feature is enabled, the SGSN advertizes support for location change reporting to
the GGSN by including an extension header - MS-Info-Change-Reporting indication - in the Create-PDP-Context-
Request (CPCQ) or the Update-PDP-Context-Request (UPCQ) GTP-C messages (as specified in section 6.1.5 of TS
23.060, R9).
the GGSN by including an extension header - MS-Info-Change-Reporting indication - in the Create-PDP-Context-
Request (CPCQ) or the Update-PDP-Context-Request (UPCQ) GTP-C messages (as specified in section 6.1.5 of TS
23.060, R9).
The SGSN initiates the process to report the UE location when subscription information is received from the GGSN.
The SGSN decodes the MS-Info-Change-Reporting-Action IE in the CPCR, the UPCQ, and the UPCUPCR messages
received from the GGSN that request the SGSN to check user locations.
The SGSN decodes the MS-Info-Change-Reporting-Action IE in the CPCR, the UPCQ, and the UPCUPCR messages
received from the GGSN that request the SGSN to check user locations.
The SGSN uses cell update procedures, location reporting procedures, and routing area update (RAU) procedures to
identify changes in the serving cell (2G), or in the service area (3G), or in the routing area respectively to identify
location changes. In a 2G network, the SGSN sends location information to the GGSN when it receives a cell update
from a BSC. In a 3G network, the SGSN sends information to the GGSN when it receives location reports from the
RNC. If the GGSN subscribes to the RAI changes and the UE performs an RAU, then the SGSN informs the GGSN of
the new RAI.
identify changes in the serving cell (2G), or in the service area (3G), or in the routing area respectively to identify
location changes. In a 2G network, the SGSN sends location information to the GGSN when it receives a cell update
from a BSC. In a 3G network, the SGSN sends information to the GGSN when it receives location reports from the
RNC. If the GGSN subscribes to the RAI changes and the UE performs an RAU, then the SGSN informs the GGSN of
the new RAI.
Call Flows
The following call flows illustrate system behavior when the feature is enabled.
Figure 18. 2G Subscription
1. Subscription is created.
2. Determines if subscription is present.
3. Location is sent to all GGSNs to which the UE subscribes.
2. Determines if subscription is present.
3. Location is sent to all GGSNs to which the UE subscribes.