GSM 09.02 - Version 5.3.0 - Digital cellular telecommunications - ETSI

Page 422
GSM 09.02 Version 5.3.0: August 1996
18.2.4 Procedures in the VLR
The procedures are described in figures 18.2/5, 18.2/6 and 18.2/7. These procedures make use of a
number of processes and macros not described in this subclause. The description of these can be found in
the following subclauses:
Receive_Open_Cnf subclause 21.1;
Check_Confirmation subclause 21.2;
Receive_Open_Ind subclause 21.1;
Check_Indication subclause 21.2;
Obtain_Authent_Sets_VLR subclause 21.5;
Insert_Subs_Data_VLR subclause 21.7.
Successful Outcome
On reception of the MAP_PROVIDE_ROAMING_NUMBER service indication from the HLR, the VLR will
first perform a service provision check to confirm that the service requested is supported by the PLMN.
If the service is provided and the MS is also known, the VLR will check the IMSI detached flag for the MS.
If the IMSI detached flag was not set then an MSRN will be allocated. An MSC number will already be
stored in the VLR as well as the HLR.
The MSC number provided in the MAP_PROVIDE_ROAMING_NUMBER service indication will be used
with the RAD_CONF_IND for the creation of the MSRN. That is, if the MSC number provided by the HLR
does not match the MSC number stored against the IMSI concerned the indicator "Confirmed by Radio
Contact" (RAD_CONF_IND) should be checked to establish if the number has been confirmed by radio
contact.
If the RAD_CONF_IND is set to "NOT_CONF", this means that the MSC number is out of date as it has
not been confirmed by radio contact, therefore the MSC number provided by the HLR can be used for
creation of the MSRN.
If the RAD_CONF_IND is set to "CONF", this means that the MSC number has already been confirmed by
radio contact and therefore, is more likely to be correct than the MSC number held by the HLR. The MSC
number held by the VLR can be used for creation of the MSRN.
If no IMSI record exists for the IMSI received in the MAP_PROVIDE_ROAMING_NUMBER service
indication or if no MSC number is available in the IMSI record concerned, the VLR will use the MSC
number provided by the HLR for creation of the MSRN.
NOTE: MAP version 1 described 2 options for allocating an MSRN by the VLR, either at
location updating or per terminating call set up. MAP Version 2 only supports one of
these options, that of allocating the MSRN per terminating call set-up. The option to
allocate MSRN at location updating has been deleted.
The roaming number is returned to the HLR in the MAP_PROVIDE_ROAMING_NUMBER service
response. The VLR associates the MSRN with a service indication, if such an indication was contained in
the roaming number request from the HLR. This roaming number will be used to set up the call to the
serving MSC. The procedure is then terminated in the VLR.
If the indicator "Confirmed by HLR" (HLR_CONF_IND) is set to "Not Confirmed", the VLR will also need to
request authentication and subscriber data. This is described in the procedure for MS Not Known, below.