back to TS 24.228
- Authentication: Upon receiving an integrity protected REGISTER request carrying the authentication challenge response, S-CSCF1 checks that the expected response (calculated by S-CSCF1 using XRES and other parameter as defined in RFC 3310) matches the received challenge response. If the check is successful then the user has been authenticated and the public user identity is registered in the S-CSCF.
- Cx-Put, or Diameter SAR: Server-Assignment-Request: On registering a user, S-CSCF1 informs the HSS that the user has been registered at this instance.
- Cx-Put response, or Diameter SAA: Server-Assignment-Answer: Upon being requested by S-CSCF1, the HSS will also include the user profile in the response sent to the S-CSCF.