A.26 Inviting user to Video conference by sending a REFER request to the conference focus / 5GS
34.229-53GPPInternet Protocol (IP) multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP)Part 5: Protocol conformance specification using 5G System (5GS)Release 16TSUser Equipment (UE) conformance specification
Expected sequence
|
Step |
Direction |
Message |
Comment |
|
|
UE |
SS |
|||
|
1 |
–> |
REFER |
UE sends REFER to SS referring to the conference |
|
|
2 |
<– |
202 Accepted |
The SS responds with a 202 final response |
|
|
3 |
<– |
NOTIFY |
The SS sends initial NOTIFY for the implicit subscription created by the REFER request |
|
|
4 |
–> |
200 OK |
The UE responds the NOTIFY with 200 OK |
|
|
5 |
<– |
NOTIFY |
The SS sends a NOTIFY related to REFER request to confirm that the invited user was able to join the conference |
|
|
6 |
–> |
200 OK |
The UE responds the NOTIFY with 200 OK |
|
|
7 |
<– |
NOTIFY |
Conditional: If the UE has subscribed the conference event package, the SS sends a NOTIFY for conference event package to inform that the invited user was able to join the conference |
|
|
8 |
–> |
200 OK |
Conditional: The UE responds the NOTIFY with 200 OK |
|
Specific Message Contents
REFER (Step 1)
Use the default message “MO REFER” in Annex A.2.10 of TS 34.229-1[2], applying conditions A1 and A5, with the following exceptions:
|
Header/param |
Value/remark |
|---|---|
|
Request-URI |
sip:final@conf-factory. appended with px_IMS_HomeDomainName |
|
Refer-To addr-spec |
SIP URI or tel URI of the user invited to the conference. If an active session exists, the Replaces header in the header portion of the SIP URI shall be included (mandatory inclusion is stated in NG.114 [31]) and set to the dialog ID of the active session according to RFC 3891 [40]. In this case, if the user has been invited with a tel URI, the UE shall convert the tel URI to a SIP URI according to RFC 3261 [6] clause 19.1.6. (NOTE: the dialog ID is percent encoded according to RFC 3986 [41]). |
|
Route route-param |
URIs of the Record-Route header of 183 response sent in step 4 of A.25 in reverse order |
NOTIFY (Step 3)
Use the default message “MT NOTIFY for refer package” in Annex A.2.11 of TS 34.229-1 [2], applying condition A1, with the following exceptions:
|
Header/param |
Value/remark |
|---|---|
|
Message-body |
SIP/2.0 100 Trying |
NOTIFY (Step 5)
Use the default message “MT NOTIFY for refer package” in annex A.2.11 of TS 34.229-1[2] with the following exceptions:
|
Header/param |
Value/remark |
|
Subscription-State |
|
|
substate-value |
terminated |
|
expires |
omitted from the request |
|
reason |
noresource |
|
Message-body |
SIP/2.0 200 OK |
NOTIFY (Step 7)
Use the default message “NOTIFY for conference event package” in annex A.5.3 of TS 34.229-1[2] with the following exceptions:
|
Header/param |
Value/remark |
|
Message-body |
<?xml version="1.0" encoding="UTF-8"?> <conference-info xmlns="urn:ietf:params:xml:ns:conference-info"> entity="sip:final@conf-factory. appended with px_IMS_HomeDomainName" state="partial" version="1" <users> <user entity=" SIP URI or tel URI of the invited user"> <endpoint entity=" Contact URI of the invited user"> <status>connected</status> <joining-method>dialled-in</joining-method> <media id="1"> <type>audio</type> <label>11223</label> <src-id>random SSRC value</src-id> <status>sendrecv</status> </media> <media id="2"> <type>video</type> <label>11224</label> <src-id>random SSRC value</src-id> <status>sendrecv</status> </media> </endpoint> </users> </conference-info> |