7.5 Regional Restriction Procedure

23.1193GPPGateway Location Register (GLR)Release 17Stage 2TS

In the case that GLR is introduced, during second and subsequent location updating, there is no interaction between the GLR and the HLR. However, the regional restriction service needs the location updating procedure towards the HLR.

The GLR stores the Zone Code List sent by the HLR in the Insert Subscriber Data message. On the location updates the GLR sends its stored Zone Code list to the VLR and/or SGSN (refer to figure 7.2/10). The GLR stores also the MSC area restricted flag and/or the SGSN are restricted flag. These flags are set "False" if the location updating procedure executed successfully.

When the GLR receives the Insert Subscriber Data Acknowledge message indicating "MSC area restricted" or "SGSN area restricted" and the MSC area restricted flag or the SGSN area restricted flag is set as "False", the GLR initiates the location updating procedure toward the HLR. In addition, the GLR sets the MSC area restricted flag or the SGSN area restricted flag "True". Also, the HLR sets the MSC area restricted flag or the SGSN area restricted flag "True", and the location updating for the IMSI is rejected. These flags contribute to the "MS Not Reachable" state for handling of terminating traffic (i.e. mobile terminated call and mobile terminated SMS and so on) in the HLR.

Figure 7.5/1: Regional Restriction Procedure (MS Enters a restricted Area)

When the GLR receives the Insert Subscriber Data Acknowledge message indicating "MSC area restricted" or "SGSN area restricted" and the MSC area restricted flag or the SGSN area restricted flag is set as "True", The GLR reject the location updating procedure for the IMSI. No interaction with the HLR is needed.

When the user returns to an MSC area that is not restricted due to regional subscription (see figure 7.2/11), i.e., when the GLR receives the Insert Subscriber Data Acknowledge message NOT indicating "MSC area restricted" or "SGSN area restricted" and the MSC area restricted flag or the SGSN area restricted flag is set as "True", the GLR initiates the location updating procedure toward the HLR.

Figure 7.5/2: Regional Restriction Procedure (MS leaves the restricted area)