7.3.2 Detach procedure

23.1193GPPGateway Location Register (GLR)Release 17Stage 2TS HLR-Initiated Detach Procedure

The HLR-Initiated Detach procedure is initiated by the HLR. The HLR uses this procedure for operator-determined purposes to request the removal of a subscriber’s MM and PDP contexts at the SGSN. The HLR-Initiated Detach Procedure is illustrated in Figure 7.3/9. Each step is explained in the following list.

FigureĀ 7.3/9: HLR-Initiated GPRS Detach Procedure

1) If the HLR wants to request the immediate deletion of a subscriber’s MM and PDP contexts from the SGSN, the HLR shall send a Cancel Location (IMSI, Cancellation Type) message to the SGSN via GLR with Cancellation Type set to Subscription Withdrawn.

2) The SGSN informs the MS that it has been detached by sending Detach Request (Detach Type) to the MS. Detach Type shall indicate that the MS is not requested to make a new attach and PDP context activation.

3) The active PDP contexts in the GGSNs regarding this particular MS are deactivated by the SGSN sending Delete PDP Context Request (TID) messages to the GGSNs. The GGSNs acknowledge with Delete PDP Context Response (TID) messages.

4) If the MS was both IMSI- and GPRS-attached, the SGSN sends a GPRS Detach Indication (IMSI) message to the VLR. The VLR removes the association with the SGSN and handles paging and location updating without going via the SGSN.

5) The MS sends a Detach Accept message to the SGSN any time after stepĀ 2.

6) The SGSN shall confirm the deletion of the MM and PDP contexts with a Cancel Location Ack (IMSI) message via GLR. Functional requirements of GLR Process Cancel_GPRS_Location_GLR

Figure 7.2/10 shows SDL chart for Process Cancel_GPRS_Location_GLR. This process is initiated from the HLR.

Figure7.3/10: Process Cancel_GPRS_Location_GLR