09.183GPPGeneral Packet Radio Service (GPRS)Gs interface layer 3 specificationServing GPRS Support Node (SGSN) - Visitors Location Register (VLR)TS
This chapter decribes the SGSN behaviour towards the VLR as a consequence of an HLR reset.
13.1 General description
In the case of an HLR failure, the HLR informs the associated SGSNs about the recovery from an internal failure that has affected the association with the SGSNs according to the HLR reset procedure specified in 3GPP TS 09.02.
This information is used in the SGSN to trigger the VLR to perform a location update towards the HLR in order to restore the HLR subscriber data,
13.2 Procedures in the SGSN
Upon receipt of a HLR reset indication from the HLR, the SGSN shall set the NGAF for all registered MSs in the SGSN for which a valid MSC/VLR-association exists.
Upon detection of any activity (either signalling or data) from the MS, the SGSN shall report to the VLR if the NGAF is set for this MS. If the SGSN detects GPRS signalling that leads to a procedure towards the VLR, the SGSN shall follow this procedure and reset the NGAF. If the SGSN detects activity that does not lead to any procedure towards the VLR, the SGSN shall send an BSSAP+-MS-ACTIVITY-INDICATION message towards the VLR and reset the NGAF. The activity indication may be delayed by the SGSN for a maximum operator-configuration depending time period to avoid high signalling load.