GSM 09.02 - Version 5.3.0 - Digital cellular telecommunications - ETSI

Page 317
GSM 09.02 Version 5.3.0: August 1996
When the VLR accepts the dialogue, it will return a MAP_CANCEL_LOCATION confirmation, containing:
- no parameter, indicating successful outcome of the procedure;
- a user error, provider error or a data error indicating unsuccessful outcome of the procedure.
In case of unsuccessful outcome or if a MAP_P_ABORT indication has been received, the HLR may
repeat the MAP_CANCEL_LOCATION request later, where the number of repeat attempts and time in
between are HLR operator options, depending on the error returned by the VLR.
16.1.2.3 Detailed procedure in the VLR
Opening of the dialogue is described in the macro Receive_Open_Ind in subclause 21.1, with outcomes:
- reversion to version one procedure;
- procedure termination; or
- dialogue acceptance, with processing as below.
If the VLR process receives a MAP_NOTICE indication, it terminates the dialogue by sending a
MAP_CLOSE request.
If the VLR process receives a MAP_CANCEL_LOCATION indication from the HLR (see figure 16.1.2/3),
the parameters are checked first (macro Check_Indication, see subclause 21.2). In case of parameter
problems the appropriate error is sent in the MAP_CANCEL_LOCATION response.
If the MAP_CANCEL_LOCATION indication contains both the IMSI and the LMSI, the VLR checks whether
the stored IMSI matches the received IMSI. If it does not, the VLR attempts to process the request using
the IMSI received from the HLR to define the subscriber record to be deleted.
Thereafter the VLR checks whether the subscriber identity provided is known in the VLR:
- if so, the data of the subscriber are deleted from VLR table and a MAP_CANCEL_LOCATION
response is returned without any parameters;
- if not, location cancellation is regarded as being successful, too, and the
MAP_CANCEL_LOCATION response is returned without any parameters.
In either case, after sending the MAP_CANCEL_LOCATION response the VLR process releases any
TMSI which may be associated with the IMSI of the subscriber, terminates the dialogue (MAP_CLOSE
with Release Method Normal Release) and returns to the idle state.