GSM 09.02 - Version 5.3.0 - Digital cellular telecommunications - ETSI

CUG Outgoing Access
Page 111
GSM 09.02 version 5.3.0: August 1996
This parameter may only be present in the request and indication if the CUG Interlock Code is also
provided. This information is received from ISUP. This parameter will only be present in the response and
confirm, if the Incoming Call Setup Result indicates forward and the call is to be treated as a CUG Call,
following the CUG Call Authorization check in the VLR.
Number of Forwarding
If the call has already been forwarded this parameter will contain a count of the number of times the call
has been forwarded, if it is provided by ISUP.
Incoming Call Setup Result
This parameter if present will indicate either success or forward. If the result indicates forward then the
Forwarding Data and optionally MSISDN must also be present.
Forwarding Data
This is the address of the subscriber to whom the call should be connected. The parameter will contain the
forwarded-to-number and if required the forwarding options.
MSISDN
This is the mobile subscriber ISDN identity of the called party. This is an operator dependant inclusion.
User error
This parameter is sent by the responder when an error is detected and if present, takes one of the
following values:
- Unallocated Roaming Number;
The MS has been identified by an MSRN, and this MSRN is not allocated.
- Unknown Subscriber;
- Absent Subscriber;
This indicates that there is no call forwarding and either the IMSI detached flag was set in the VLR
or paging was unsuccessful.
- Impossible Call Completion;
This indicates that the call will not be forwarded and shall be released, e.g. call forwarding on busy
subscriber and call waiting services are not active.
- Forwarding Violation;
A call forwarding condition applies but the incoming call has already been forwarded as many times
as allowed.
- CUG Reject;
The value of this error cause will indicate the reason for CUG reject.
- Unexpected Data Value;
- Data Missing;
- System Failure.
See subclause 5.6 for a definition of these reasons.
Provider error
These are defined in subclause 5.6.