- The registration expires in UE1. UE1 reregisters by sending a new REGISTER request. This request is sent to the same P-CSCF with which UE1 initially registered.
-
Authorization:
It carries authentication information. The private user identity (user1_private@home1.net) is
carried in the username field of the Digest AKA protocol. As this is a re-registration process,
the cached information (realm, nonce, algorithm, uri, response) is also sent.
NOTE: The actual nonce value in the WWW-Authenticate header field is encoded in base64, and it may look like: nonce="A34Cm+Fva37UYWpGNB34JP" - Security-Client: Lists the supported algorithm(s) by UE1. The values spi-c, spi-s, port-c and port-s are new parameter values and will not be used for security association setup in case the request is answered with 200 (OK).
- Security-Verify: Contains the security agreement as represented by the previously received Security-Server header.
- Upon receiving this request P-CSCF1 will detect that it already has a registration record for UE1 and will reset its SIP registration timer for UE1 to the Expires time in this request.