3GPP TS 24.228 -- IMS Signalling flows for Register
|
|
|
|
|
|
|
| Session Initiation: Non Hiding |
| |
|
| |
|
| |
|
| |
|
| |
|
|
|
|
| Session Initiation: Hiding |
| |
|
| |
|
| |
|
| |
|
| | |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| - |
The HSS information indicates that the subscriber is registered and authenticated, and that the S-CSCF
has been allocated to this subscriber.
| |
| - |
This signalling flow assumes that:
1. the same PDP Context allocated during the initial registration scenario is still used for reregistration
2. the DHCP procedure employed for P-CSCF discovery is not needed
3. the S-CSCF selection procedure invoked by the I-CSCF is not needed.
|
|
|
|
|
|
|
|
| - |
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.
|
|
|
|
|
|
|
|
|
| - |
Based on the user's URI, P-CSCF1 determines that UE1 is registering from a visiting domain and
performs the DNS queries to locate the I-CSCF in the home network. The look up in the DNS is based
on the domain name specified in the Request URI. The DNS provides P-CSCF1 with the address of
the I-CSCF in the home network.
NOTE: The P-CSCF must not use the I-CSCF address cached as a result of
the previous registration.
|
|
|
|
|
|
|
|
| - |
P-CSCF1 removes the Security-Client header and associated "sec-agree" option-tags prior to
forwarding the request. As the Proxy-Require header is empty, it removes this header completely.
| |
| - |
Path:
This is P-CSCF1 URI and is included to inform S-CSCF1 where to route terminating requests.
| |
| - |
Require:
This header is included to ensure that the recipient correctly handles the Path header. If the
recipient does not support the path header, a response will be received with a status code of
420 and an Unsupported header indicating "path". Such a response indicates a
misconfiguration of the routing tables and the request has been routed outside the IM CN
subsystem.
| |
| - |
P-Visited-Network-ID:
It contains the identifier of P-CSCF1 network at the home network.
| |
| - |
P-Charging-Vector:
P-CSCF1 inserts this header and populates the icid parameters with a globally
unique value.
|
|
|
|
|
|
|
|
|
| - |
Cx-Query, or Diameter UAR: User-Authorization-Request:
The I-CSCF makes a request for information related to the Subscriber registration status by sending the
private user identity ("user1_private@home1.net"), public user identity ("user1_public1@home1.net")
and visited domain identifier ("Visited Network Number 1") to the HSS.
| |
| - |
Cx-Query response, or Diameter UAA: User-Authorization-Answer:
The HSS returns the S-CSCF
required capabilities and the I-CSCF uses this information to select a suitable S-CSCF.
|
|
|
|
|
|
|
|
| - |
Upon receiving this request S-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.
|
|
|
|
|
|
|
|
|
|
| - |
Update registration timer: As the REGISTER request arrived integrity protected, S-CSCF1 does not need
to challenge the user, but
just update the registration timer to the value requested by the user (if the policy of the network allows it).
NOTE: S-CSCF1 is allowed to challenge the user. If S-CSCF1 decides to challenge the user, the call flow
will be similar to the one presented in "Registration: user not registered".
|
|
|
|
|
|
|
|
| - |
Service-Route:
S-CSCF1 inserts the Service-Route header that includes its own URI including a character
string in the user part to differentiate mobile originating requests from mobile terminating
requests.
|
|
|
|
|
|
|
|
| - |
P-CSCF1 saves the value of the Service-Route header and associates it with UE1. P-CSCF1 then
forwards 200 (OK) response from I-CSCF1 to UE1 indicating that the registration was successful.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
