GSM 09.02 - Version 5.3.0 - Digital cellular telecommunications - ETSI

18.4.3 Procedures in the VLR
Page 463
GSM 09.02 Version 5.3.0: August 1996
The procedure is shown in figures 18.4/5 and 18.4/6. 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:
Check_Confirmation subclause 21.2;
Process_Access_Request_VLR subclause 21.4;
Receive_Open_Ind subclause 21.1;
Check_Indication subclause 21.2.
Successful Outcome
Once the procedures initiated by the MAP_PROCESS_ACCESS_REQUEST service request have been
successfully completed, the MSC will then initiate a MAP_SEND_INFO_FOR_OUTGOING_CALL service
request. This is to request the VLR to provide information to allow the MSC to handle an outgoing call set
up request from an MS. The VLR will check the parameters and data for errors.
If a specific Bearer Service or Teleservice has been requested by the MS, the VLR will then perform the
subscription check for the provision of the service. The VLR will also check the activation status of the
supplementary services and the status of call barring services (i.e. barring of outgoing calls, conditional
barring of outgoing calls or administrative reasons such as bad payer).
If the calling MS is part of a closed user group (CUG), the MSC will have passed any CUG information
(received from the MS) to the VLR in the MAP_SEND_INFO_FOR_OUTGOING_CALL service request.
The VLR will perform the authorization checks on the call, this authorization is determined by the
information received from the MSC, the subscription information held by the VLR and the call scenario. It is
possible that a CUG call may be implicitly invoked without CUG information being passed to the VLR in the
MAP_SEND_INFO_FOR_OUTGOING_CALL service indication. In this instance, the VLR will just return
the CUG_Index value to the MSC. The procedures for authorizing a CUG call and the information to be
returned to the serving MSC are described in more detail in TS GSM 03.85.
If the calling MS has passed all checks the VLR will instruct the MSC to set up the call by sending a
MAP_COMPLETE_CALL service request to the MSC. This request may contain parameters related to the
subscription, e.g. supplementary services and basic services. On successful completion of the
MAP_COMPLETE_CALL service, this procedure is then terminated in the VLR.
Parameter or data errors
If the VLR detects any parameter or data errors in MAP_SEND_INFO_FOR_OUTGOING_CALL service
indication from the MSC, the VLR will reject the service request. The
MAP_SEND_INFO_FOR_OUTGOING_CALL service parameter user error will be set to either "Data
Missing" or "Unexpected Data Value". This response is returned to the MSC and the procedures in the
VLR will be terminated.
Service Provider Failure
Once a dialogue between the MSC and VLR or VLR and HLR is established, a MAP_P_ABORT service
indication may be received, at any stage, from the MAP Service Provider. This will abort the dialogue, see
clause 5 for a definition of the abort reasons.
Call Released by Calling MS
The call may be released by the calling subscriber at any stage during the outgoing call set up procedure.
The VLR will be informed of this event by the MSC sending a MAP_U_ABORT service indication. The VLR
will then terminate all procedures associated with the call.