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.