3GPP TS 24.228 -- IMS Signalling flows for Session Initiation
|
|
|
|
|
|
|
| Session Initiation: Non Hiding |
| |
|
| |
|
| |
|
| |
|
| |
|
|
|
|
| Session Initiation: Hiding |
| |
|
| |
|
| |
|
| |
|
| | |
|
|
|
|
| - |
Mobile origination, roaming, with I-CSCF in home network
providing configuration independence
|
| - |
Single Network Operator performing Origination and Termination
|
| - |
Mobile Termination, located in home network
|
|
|
|
|
|
|
|
|
|
|
|
| - |
UE1 is located in a visited
network, and determines the P-CSCF via the CSCF discovery procedure. During registration, the home network
allocates an S-CSCF. The home network advertises an I-CSCF as the entry point from the visited network, who
forwards requests to the S-CSCF.
|
| - |
P-CSCF1 knows the name/address of the S-CSCF from a prior Registration performed by the UE.
|
|
|
|
|
|
|
|
| - |
Request-URI:
Contains the public user identity of the called user.
|
| - |
Via:
Contains the IPv6 address or FQDN (fully qualified domain name)
of the originating UE.
|
| - |
Route:
Contains the P-CSCF address learnt during P-CSCF discovery,
plus the elements from the
Service-Route header from registration. The P-CSCF URI contains the port number learnt
during the security agreement negotiation.
|
| - |
P-Preferred-Identity:
The user provides a hint about the identity
to be used for this session.
|
| - |
P-Access-Network-Info:
UE1 provides the access-type and access-info,
related to the serving access.
|
| - |
Privacy:
The user does not require privacy,
therefore the Privacy header is set to the value "none" as
specified in RFC 3325 and RFC 3323.
|
| - |
Security-Verify:
Contains the security agreement
as represented by the received Security-Server header.
|
| - |
Contact:
SIP URI that contains the IP address or FQDN of the originating UE.
|
| - |
SDP:
Contains the set of codecs supported by UE1 and desired by the user at UE1 for this session.
|
|
|
|
|
|
|
|
| - |
P-CSCF1 adds itself to the Record-Route header and Via header. As the request is forwarded to an
interface that is not compressed, the own P-CSCF SIP URI does not contain the "comp=sigcomp"
parameter.
|
| - |
P-CSCF1 removes the Security-Verify header and associated "sec-agree" option-tags prior to
forwarding the request. As the Proxy-Require header is empty, it removes this header completely.
|
| - |
P-Asserted-Identity:
P-CSCF1 inserts the SIP URI in
the P-Asserted-Identity header field and it also removes the
P-Preferred-Identity header field.
|
| - |
P-Charging-Vector:
P-CSCF1 inserts this header and
populates the icid parameters with a globally unique value.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| - |
Route:
As S-CSCF1 knows that the next hop I-CSCF is in the same home network (and therefore, a loose
router), it includes a Route header.
|
| - |
P-Charging-Vector:
S-CSCF1 adds the identifier of its own
network to the originating Inter Operator
Identifier (IOI) parameter of this header.
|
| - |
I-CSCF2 sends a query to the HSS to find out the S-CSCF of the called user. The HSS responds with
the address of the current S-CSCF for the terminating subscriber.
|
|
|
|
|
|
|
|
| - |
I-CSCF2 does not add itself to the Record-Route header, as it has no need to remain in the
signalling path once the session is established.
|
|
|
|
|
|
|
|
| - |
Route:
Built from the Path header stored at registration.
|
| - |
Via:/Record-Route:
S-CSCF2 adds itself.
|
| - |
P-Called-Party-ID:
Includes the dialled URL with its parameters.
|
|
|
|
|
|
|
|
| - |
Via:
P-CSCF2 adds the port number negotiated during the security agreement and the
comp=sigcomp parameter to its Via header.
|
| - |
Record-Route:
P-CSCF2 adds the port number negotiated during the security agreement and the
comp=sigcomp parameter to its own URI.
|
| - |
P-Media-Authorization:
A P-CSCF generated authorization token. This particular example shows a Policy-Element
generated by "pdf1.home1.net" with credentials "31S14621".
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| - |
P-Access-Network-Info:
UE2 provides the access-type and access-info, related to the serving access network.
|
| - |
To:
a tag is added to the To header.
|
| - |
Contact:
Contains a SIP URI with the IP address or FQDN of UE2. It includes the
comp=sigcomp parameter.
|
| - |
SDP:
Contains the set of codecs supported by UE2. It requests a confirmation of the
QoS preconditions for establishing the session.
|
|
|
|
|
|
|
|
| - |
Record-Route:
P-CSCF2 rewrites the Record-Route header field value to remove the port number
used for the security association and the comp=sigcomp parameter from its own URI.
|
| - |
P-Asserted-Identity:
P-CSCF2 inserts the default SIP URI of the user in the P-Asserted-Identity header field.
|
|
|
|
|
|
|
|
| - |
P-Charging-Vector:
S-CSCF2 adds the identifier of its own network to the terminating Inter Operator
Identifier (IOI) parameter of this header and puts back the originating IOI parameter.
|
| - |
P-Charging-Function-Addresses:
S-CSCF2 passes this header to I-CSCF2 for charging.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| - |
Record-Route:
Header entries of the home network of I-CSCF1 are tokenized. The I-CSCF itself and the UE
addresses are not subject to tokenization.
|
|
|
|
|
|
|
|
| - |
Record-Route:
P-CSCF1 rewrites the Record-Route header to add the port number negotiated
during the security agreement and the comp=sigcomp parameter to its own SIP URI.
|
| - |
P-Media-Authorization:
a P-CSCF generated authorization token; this particular example shows a Policy-Element
generated by "pdf2.visited2.net" with credentials "9BV3072"; "00" at the end
of the authorization token is required to pad to a multiple of 4 bytes.
|
|
|
|
|
|
|
|
