A.1 ACR termination towards UE-B
24.6113GPPAnonymous Communication Rejection (ACR) and Communication Barring (CB) using IP Multimedia (IM) Core Network (CN) subsystemProtocol specificationRelease 17TS
Figure A.1.1: ACR termination towards UE-B
1 to 2. INVITE request (UE to S-CSCF) – see example in figure A.1.1.
The incoming INVITE request is sent to the S-CSCF serving UE-B. The INVITE request includes a Privacy header field set to one of the following values: "id" or "header" or "user".
3. Evaluation of initial filter criteria.
The initial Filter criteria indicates that the called user is subscribed to the ACR service. Therefore the S-CSCF forwards the INVITE request to the ACR AS.
4 to 5. INVITE request (S-CSCF to AS) – see example in figure A.1.1.
INVITE is sent to the AS.
6 to 8. 433 (Anonymity Disallowed) response. (AS to UE) – see example in figure A.1.1.
AS has identified that the call is anonymous and answers with a 433 (Anonymity Disallowed) response.
9 to 10. The originating party acknowledges the final response with ACK.