Content for TS 24.186 Word version: 19.4.0

1… 4… 9… 9.3… 9.3.2.2… 9.3.3… 9.3.3.2… 9.4… 10… 10.11… A… A.1.2… A.1.2.2… A.1.3… A.1.3.2… A.1.3.3… B… C…

5.1 General 5.2 UE 5.3 IMS AS 6.1 Provision/withdrawal 7.1 IMS Session Control 7.2 IMS communication service identifier (ICSI) 8.1 Procedures at the UE 8.2 Procedures at the IMS AS
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4 General p. 11

According to TS 23.228, IMS multimedia telephony service supporting IMS data channel includes IMS data channel capability negotiation and IMS data channel setup. AR communication which is application based on IMS data channel capability, provisioned to the UE as an IMS data channel application, includes respective application domain specific media capability negotiation and media processing (e.g. AR communication).

5 Functional entities p. 12

5.1 General p. 12

This clause specifies the functionalities of the functional entities for IMS data channel.

5.2 UE p. 12

An UE supporting IMS data channel has the following functionalities:

support IMS data channel capability negotiation;
support bootstrap data channel and application data channel establishment and management;
may support IMS data channel multiplexing and its capability negotiation.

Additionally, the UE supporting the IMS data channel capability and provisioned with AR communication, which is an application having IMS data channel capability, supports the following functionalities:

support application's domain specific media capability exchange; and
support application's domain specific media processing.

5.3 IMS AS p. 12

The IMS AS interacts with the DCSF and the MF.

For functionalities of the IMS AS supporting IMS data channel refer to clause AC.2.2.4 of TS 23.228.

For the IMS AS interaction with the Media Function (MF) refer to TS 29.176.

For the IMS AS interaction with the Data Channel Signalling Function (DCSF), NEF and Trusted AF refer to TS 29.175.

6 Operational requirements p. 12

6.1 Provision/withdrawal p. 12

IMS Multimedia Telephony communication service enhanced to support IMS data channel is provided after prior arrangement with the service provider.

IMS Multimedia Telephony communication service enhanced to support IMS data channel is withdrawn at the user's request or for administrative reasons.

7 Basic communication p. 12

7.1 IMS Session Control p. 12

The IMS multimedia telephony communication enhanced to support the IMS data channel applications shall support data channel media specified in clause 6.2.10 of TS 26.114 in addition to MMTel media types listed in TS 22.173. The session control procedures for the different media types shall be in accordance with TS 24.229, TS 24.173, and clause 9.

The usage of IMS data channel media streams in MMTel session is negotiated using the SDP offer/answer procedures defined in RFC 3264. If the received SDP offer contains IMS data channel media description(s) and if the receiving entity determines not to accept the requested IMS data channels, the receiving entity shall reject the offered data channel media description(s) by setting the port number of the rejected data channel media description(s) to zero in created SDP answer.

7.2 IMS communication service identifier (ICSI) p. 13

The MMTel service enhanced to support IMS Data Channel shall use the ICSI value defined in clause 5.1 of TS 24.173. The UE and IMS AS shall handle the ICSI value as specified in TS 24.229.

8 IMS data channel applications p. 13

8.1 Procedures at the UE p. 13

8.1.1 General |R19| p. 13

Once an MMTel session with the bootstrap data channels have been established, if the IMS data channel applications are available, based on the IMS data channel applications list received via the established bootstrap data channel, the UE shall download through the established bootstrap data channel the IMS data channel applications. The UE shall follow the procedures in clause 9.3.2.1.3.2 to set up an application data channel and include in the re-INVITE request the updated SDP offer with negotiated bootstrap data channel media description, the requested application data channel media description as well as the associated data channel application binding information (provided within the "a=3gpp-req-app" SDP attribute), according to TS 23.228 and TS 26.114. The UE receiving the re-INVITE request shall identify the requested application data channel and the corresponding IMS data channel application, select an established bootstrap data channel to download through if it is not available on the UE, based on the associated data channel application binding information.

Upon receipt of a re-INVITE request initiated by the IMS AS to update an existing MMTel session with established bootstrap data channels for adding an application data channel requested by a DC AS, the UE accepting the requested application data channel shall identify the corresponding IMS data channel application and select an established bootstrap data channel to download through if it is not available on the UE, based on the associated data channel application binding information.

8.1.2 Support of Standalone IMS Data Channel Session |R19| p. 13

If the originating UE has downloaded the data channel application, application data channel can be established together with bootstrap data channel during standalone IMS data channel session establishment.

If the terminating UE received the INVITE request to set up the bootstrap and application data channel simultaneously, the UE shall identify the data channel application in the application binding information (provided within the "a=3gpp-req-app" SDP attribute) is available or not, and:

if not available, it shall accept the bootstrap data channel and reject the application data channel to indicate that the data channel application is desired to be downloaded and download the application data channel through the established bootstrap data channel; or
if available, it shall follow the procedure in clause 9.3.3.1.6.3 to establish the requested bootstrap data channel and application data channel.

If the UE did not download the data channel application, the UE shall establish an IMS session with only the bootstrap data channel towards a PSI, download the application through the established bootstrap data channel, and then establish an standalone IMS session with the associated application data channel and required bootstrap data channels towards peer UE; or initiate an IMS session with only the bootstrap data channel towards peer UE, and download the application through the established bootstrap data channel then add the associated application data channel during standalone IMS data channel session establishment.

8.2 Procedures at the IMS AS p. 13

8.2.1 General |R19| p. 13

After an MMTel session with the bootstrap data channels have been established, if the IMS AS received a re-INVITE request with an SDP offer containing application data channels media descriptions (identified by "dcmap" attribute lines containing "stream-id" parameter set to values starting at 1000 and associated "a=3gpp-req-app" attribute lines as specified in TS 26.114), the IMS AS shall notify the DCSF, may trigger the reservation or update of corresponding application data channel media resources upon the instruction from the DCSF and shall send re-INVITE request with the SDP offer containing the requested application data channel and related bootstrap data channel media descriptions according to the specific data channel application use case (e.g. P2P/P2A/P2A2P), following the procedures in TS 23.228, and clauses 9.3.2.2.2.2 and 9.3.3.2.2.2.

8.2.2 Support of Standalone IMS Data Channel session |R19| p. 14

The application data channel can be established along with the bootstrap data channel. If the IMS AS receives the INVITE to establish the bootstrap data channel and the application data channel, it shall check whether the user is authorized to use standalone data channel. If the user is authorized to use standalone data channel, the IMS AS shall notify the DCSF and reserve the data channel media as specified in clause 9.3.2.1.6.4 and 9.3.3.1.6.3.