Content for TS 24.186 Word version: 19.0.0

1… 4… 9… 9.3… 9.3.3… 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…

9.3.3 Terminating side 9.3.3.1 Procedures at the UE 9.3.3.1.1 General 9.3.3.1.2 IMS bootstrap data channel setup in conjunction with MMTel session setup 9.3.3.1.3 IMS data channel setup in conjunction with MMTel session modification 9.3.3.1.3.1 IMS bootstrap data channel establishment 9.3.3.1.3.2 IMS application data channel establishment 9.3.3.1.4 Closing IMS application data channel in conjunction with MMTel session modification 9.3.3.1.5 Closing IMS data channel in conjunction with MMTel session release 9.3.3.2 Procedures at the serving IMS AS for the terminating UE 9.3.3.2.1 IMS bootstrap data channel establishment in conjunction with MMTel session setup 9.3.3.2.2 MMTel session modification 9.3.3.2.2.1 IMS bootstrap data channel establishment 9.3.3.2.2.2 IMS application data channel establishment 9.3.3.2.2.3 Closing application data channel 9.3.3.2.3 MMTel session release
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9.3.3 Terminating side p. 19

9.3.3.1 Procedures at the UE p. 19

9.3.3.1.1 General p. 19

The terminating UE can also setup or terminate data channels during the session modification.

9.3.3.1.2 IMS bootstrap data channel setup in conjunction with MMTel session setup p. 19

If the terminating UE determines that the UE and the network supports the IMS data channel, on the reception of SIP initial INVITE request, the terminating UE shall include the media feature tags defined in RFC 5688 for supported streaming media type with +sip.app-subtype="webrtc-datachannel" as specified in TS 26.114 in the Contact header field of SIP 18x and 2xx responses to the SIP INVITE request.

If the terminating UE receives the initial INVITE request with an SDP offer which includes the data channel media descriptions, i.e. the "m=" line containing the media set to "application", the UDP port number, the proto value set to "UDP/DTLS/SCTP" and the fmt value set to "webrtc-datachannel" and with associated "dcmap" attribute lines containing a subprotocol parameter set to "http" and any "stream-id" parameter set to values 0, 10, 100 or 110, and the terminating UE:

is not configured with IMS_DC_configuration node as specified in TS 24.275 and EFIMSDCI file specified in TS 31.103 or TS 31.102, and the terminating UE:
1. accepts the offered bootstrap data channel(s), it shall generate the SDP answer based on the TS 26.114 and RFC 8864; or
2. does not accept the offered bootstrap data channel(s), it shall set the port number(s) of the rejected data channel media stream(s) to zero in the generated SDP answer; or
is configured with IMS_DC_configuration node as specified in TS 24.275 and the DC_allowed leaf indicates that IMS data channel:
1. is allowed and if the terminating UE accepts the offered bootstrap data channel(s), it shall generate the SDP answer based on the TS 26.114 and IETF RFC 8864; or
2. is not allowed, it shall reject the offered bootstrap data channel media stream(s) by setting the port number of the rejected data channel media stream(s) to zero in the generated SDP answer,
is configured with EFIMSDCI file specified in TS 31.103 or TS 31.102 and the IMS DC Establishment Indication indicates that IMS data channel:
1. is allowed and if the terminating UE accepts the offered bootstrap data channel(s), it shall generate the SDP answer based on the TS 26.114 and IETF RFC 8864 [14]; or
2. is not allowed, it shall reject the offered bootstrap data channel media stream(s) by setting the port number of the rejected data channel media stream(s) to zero in the generated SDP answer,

and the terminating UE shall return a 18x or 2xx response to the INVITE request with the above generated the SDP answer.

9.3.3.1.3 IMS data channel setup in conjunction with MMTel session modification p. 20

9.3.3.1.3.1 IMS bootstrap data channel establishment p. 20

If the terminating UE determines that the UE and the network supports the IMS data channel, when the UE receives the re-INVITE request with an SDP offer, which includes the bootstrap data channel media descriptions, i.e. the "m=" line containing the media set to "application", the UDP port number, the proto value set to "UDP/DTLS/SCTP" and the fmt value set to "webrtc-datachannel" and with associated "dcmap" attribute lines containing a subprotocol parameter set to "http" and any "stream-id" parameter set to values 0, 10, 100 or 110, the procedure defined in clause 9.3.3.1.2 applies.

If the terminating UE wants to setup a bootstrap data channel during the session modification by sending SIP re-INVITE request, the procedure defined in clause 9.3.2.1.3.1 applies.

9.3.3.1.3.2 IMS application data channel establishment p. 20

If the terminating UE has an established bootstrap data channel associated with the MMTel session available and if the UE receives the re-INVITE request with an SDP offer which includes data channel media descriptions for the bootstrap data channel, as well as the requested application data channel and the associated data channel application binding information (provided within the "a=3gpp-req-app" SDP attribute), and the terminating UE accepts the offered application data channel, it shall return a 183 (Session Progress) or 200 (OK) response to the re-INVITE request with the generated the SDP answer based on the TS 26.114 and RFC 8864.

If the terminating UE wants to setup an application data channel, the procedure defined in clause 9.3.2.1.3.2 applies.

9.3.3.1.4 Closing IMS application data channel in conjunction with MMTel session modification p. 20

If the terminating UE receives a re-INVITE request including an SDP offer in which the UDP port number of the data channel media description was set to zero or the "a=dcmap" line associated with an application data channel was removed from the data channel media description, and the terminating UE accepts the application data channel termination, it shall return a 200 (OK) response to the re-INVITE request with the generated SDP answer based on the RFC 8864.

If the terminating UE wants to close an established application data channel during the session modification by sending re-INVITE request, the procedure defined in clause 9.3.2.1.4 applies.

9.3.3.1.5 Closing IMS data channel in conjunction with MMTel session release p. 21

When the UE releases an MMTel session that has associated bootstrap and application data channels, the UE shall apply procedures defined in clause 5.1.5 of TS 24.229 and shall close bootstrap and application data channels.

9.3.3.2 Procedures at the serving IMS AS for the terminating UE p. 21

9.3.3.2.1 IMS bootstrap data channel establishment in conjunction with MMTel session setup p. 21

Upon receipt of a SIP initial INVITE request with the SDP offer including IMS data channel media descriptions from the originating network, if the IMS AS determined that the terminating registered UE:

supports IMS data channel capabilities and is authorized to use IMS data channel, the IMS AS shall notify the DCSF about a session establishment request event and shall not send a INVITE request to the S-CSCF until receiving an acknowledgement from the DCSF. Based on the received Media instruction set from the DCSF, the IMS AS shall select the MF and request the MF to allocate required data channel media resources. Based on the response of the reserved media resource from the MF, the IMS AS shall
- delete the remote bootstrap data channel media description for the originating UE (the media line with the "dcmap" attribute containing a subprotocol parameter set to "http" and "stream-id" parameter set to values 100 and 110 and "a=3gpp-bdc-used-by" attribute with "bdc-used-by" parameter set to value "sender"), i.e. the remote bootstrap data channel between originating UE and terminating network in the SDP offer.
- replace the IP address represented in the "c=" line, the UDP port number in the "m=application" line as well as the DC endpoint information represented as the attribute lines including the "a=tlsId", "a=sctp-port", "a=fingerprint" and "a=setup" line in the remote bootstrap data channel media description for the terminating UE (the media line with the "dcmap" attribute containing a subprotocol parameter set to "http" and "stream-id" parameter set to values 100 and 110 and "a=3gpp-bdc-used-by" attribute with "bdc-used-by" parameter set to value "receiver"), i.e. the remote bootstrap data channel between terminating UE and originating network, with the media resource information for the termination towards the terminating UE if the media in anchored on the MF; and
  - generate and add the local bootstrap data channel media description for the terminating UE (the media line with the "dcmap" attribute containing a subprotocol parameter set to "http" and "stream-id" parameter set to values 0 and 10), i.e. the local bootstrap data channel between the terminating network and terminating UE to the SDP offer.
upon the reception of a successful acknowledgement from the DCSF to the session establishment request event notification, the IMS AS shall send the initial INVITE request with the modified SDP offer via the S-CSCF towards the terminating registered UE of the served user, which support the IMS data channel capabilities; or
does not support IMS data channel capabilities or is not authorized to use IMS data channel, then based on the operator policy the IMS AS shall determine whether to remove from the SDP offer media lines related to the IMS data channels:
1. if the operator policy indicates removal of media lines related to the IMS data channels, the IMS AS shall not trigger the DC media resource reservation and the IMS AS shall remove from the received SDP offer media lines describing the bootstrap data channel(s) i.e.:
  - "dcmap" attribute lines containing a subprotocol parameter set to "http" and "stream-id" parameter set to values 0, 10, 100 and 110; and
  - if present, "a=3gpp-bdc-used-by:" attribute lines,
  associated with the "m=" line containing the media set to "application", the UDP port number, the proto value set to "UDP/DTLS/SCTP" and the fmt value set to "webrtc-datachannel". If there are no other "dcmap" attribute lines that contain a subprotocol parameter set to value other than "http", the IMS AS shall remove any other SDP media attribute lines associated with that m line e.g., "sctp-port", "max-message-size", "tls-id", "a=setup", "a=3gpp-qos-hint" SDP attribute lines. The IMS AS shall send the SIP initial INVITE request with the modified SDP offer to the S-CSCF towards the terminating registered UE of the served user.

Upon receipt of the 18x or 2xx response on the initial INVITE message including the SDP answer which includes the data channel media description, the IMS AS shall notify the DCSF about corresponding session event (session establishment progress (i.e. receiving the 183 (Session Progress) response ), session establishment alerting (i.e. receiving the 180 (Ringing) response) or session establishment success (i.e. receiving the 200 (OK) response on the INVITE request) event) and shall request the MF to update the media resources. Based on the response from the MF, the IMS AS shall:

generate and add the remote bootstrap data channel media description for the originating UE (the media line with the "dcmap" attribute containing a subprotocol parameter set to "http" and "stream-id" parameter set to values 100 and 110 and "a=3gpp-bdc-used-by" attribute with "bdc-used-by" parameter set to value "sender") in the SDP answer, i.e. the remote bootstrap data channel between originating UE and terminating network;
replace the IP address represented in the "c=" line, the UDP port number in the "m=application" line as well as the DC endpoint information represented as the attribute lines "a=tlsId", "a=sctp-port", "a=fingerprint" and "a=setup" line within the remote bootstrap data channel media description for the terminating UE (the media line with the "dcmap" attribute containing a subprotocol parameter set to "http" and "stream-id" parameter set to values 100 and 110 and "a=3gpp-bdc-used-by" attribute with "bdc-used-by" parameter set to value "receiver"), i.e. the remote data channel between terminating UE and originating network, with the DC endpoint information for the termination towards the originating network allocated by the MF; and
delete the bootstrap data channel media description (the media line with the "dcmap" attribute containing a subprotocol parameter set to "http" and "stream-id" parameter set to values 0 and 10) in the SDP answer, i.e. the bootstrap data channel between terminating UE and terminating network;

Upon the reception of an acknowledgement from the DCSF to the corresponding notification, the IMS AS shall include the modified SDP answer for data channel to originating network and send the 18x or 2xx response on the initial INVITE request to the S-CSCF.

Upon receipt of a CANCEL request the initial INVITE request, the IMS AS shall notify the DCSF about the session establishment cancellation, request the MF to release the corresponding data channel media resources, and forward the CANCEL request to the S-CSCF towards the terminating UE.

Upon receipt of a 4xx, 5xx or 6xx response on the initial INVITE request from the terminating UE, the IMS AS shall notify the DCSF about session establishment failure, and request MF to release the data channel media resources.

9.3.3.2.2 MMTel session modification p. 22

9.3.3.2.2.1 IMS bootstrap data channel establishment p. 22

If the IMS AS received from the originating network a re-INVITE request with the SDP offer containing data channel media description for the bootstrap data channel establishment, if the IMS AS determined that the terminating registered UE:

supports IMS data channel capabilities and is authorized to use IMS data channel, the IMS AS shall notify the DCSF about the media change request, and modify the data channel media description in the SDP offer and send the re-INVITE request as per clause 9.3.3.2.1. Upon receipt of the 183 (Session Progress) or 200 (OK) response to the re-INVITE request, the IMS AS shall send notify the DCSF about the media change success if the data channel media is accepted or media change failure if the data channel media is rejected and modify the data channel media description in the SDP answer and send the 183 (Session Progress) or 200 (OK) response to S-CSCF as per clause 9.3.2.2.1. Upon receipt of a CANCEL request to the re-INVITE request, the IMS AS shall notify the DCSF about the media change cancellation, request the MF to release the corresponding data channel media resources, and forward the CANCEL request as per clause 9.3.2.2.1. Upon receipt of a 4xx, 5xx or 6xx response on the re-INVITE request, the IMS AS shall notify the DCSF about the media change failure and forward the response to the originating network; and
does not support IMS data channel capabilities or is not authorized to use IMS data channel, the procedure defined in clause 9.3.3.2.1 applies.

If the IMS AS received from the served user a re-INVITE request with the SDP offer containing data channel media description for the bootstrap data channel establishment, the procedure of the IMS AS in the originating network on receipt of a re-INVITE request from the originating UE defined in clause 9.3.2.2.2.1 applies.

9.3.3.2.2.2 IMS application data channel establishment p. 22

Upon receipt of a re-INVITE request with the SDP offer including:

a new application data channel media description (the media line with the "dcmap" attribute containing "stream-id" parameter set to values starting at 1000) along with the video, audio, and bootstrap data channel media descriptions from the originating network, the IMS AS shall notify the DCSF about the media change request and request MF to update the media resources.
Based on the response on the data channel media resource update from the MF as specified in TS 29.176 and media instruction from DCSF as specified in TS 29.175, the IMS AS shall:
1. delete the data channel media description (media line with the "dcmap" attribute containing "stream-id" parameter set to the values starting at 1000 and "a=3gpp-req-app " attribute with "endpoint" parameter set to value "server") if the media instruction from DCSF is to terminate the media;
2. delete the data channel media description if the media instruction from DCSF is to reject the media as specified in TS 29.175;
3. replace the IP address represented in the "c=" line, the UDP port number in the "m=application" line in the data channel media description in the SDP offer with the media resource information for the termination towards the terminating UE allocated by the MF if the media instruction from DCSF is to terminate and originate the media, and also replace the DC endpoint information represented as the attribute lines "a=tlsId", "a=sctp-port", "a=fingerprint" and "a=setup" when the media proxy configuration is HTTP proxy; and
4. generate and add a data channel media description (media line with the "dcmap" attribute containing "stream-id" parameter set to values starting at 1000 and "a=3gpp-req-app " attribute with "endpoint" parameter set to value "server") if the media instruction from DCSF is to originate a new media as specified in TS 29.175.
an existing application data channel media description in which the a new "a=dcmap" line containing the "stream-id" parameter value set to values starting at 1000 is added, the IMS AS shall notify the DCSF about media change request, and request MF to update the media resource if the media instruction from DCSF is to update the media.
The IMS AS shall send the re-INVITE request to the S-CSCF with the modified SDP offer including the modified application data channel media description or the original application data channel media description if no media instruction received from DCSF as well as the media descriptions of established video, audio and bootstrap data channels, to the terminating UE.

Upon receipt of the 183 (Session Progress) or 200 (OK) response on the re-INVITE request with the SDP answer which contains media description of the requested application data channel from the terminating UE,

if the application data channel is accepted, the IMS AS shall notify DCSF about the media change success and request the MF to update the media resources. Based on the response of the MF, the IMS AS shall
1. generate and add a data channel media description in the SDP answer by using the media information allocated on the termination towards to the originating UE on MF if the instruction from the DCSF is to terminate the media;
2. add the rejected media description and set the port number to 0 in the "m=application" line if the instruction from the DCSF is to reject the media;
3. replace the IP address represented in the "c=" line, the UDP port number in the "m=application" line in the media description in the SDP answer with the media resource information on the termination towards to the originating network allocated by the MF if the instruction from the DCSF is to terminate and originate the media and also replace the DC endpoint information as attribute lines "a=tlsId", "a=sctp-port", "a=fingerprint" and "a=setup" when the media proxy configuration is HTTP proxy; and
4. delete the media description in the SDP answer if the instruction from the DCSF is to originate a new media;
and send the 183 (Session Progress) or 200 (OK) response with the modified SDP answer on the re-INVITE request to the S-CSCF towards to the originating network after the receipt of an acknowledgement from the DCSF to the corresponding notification.
if the application data channel is rejected, the IMS AS shall notify the DCSF about media change failure and request the MF to release the media resources. The IMS AS shall send the 183 (Session Progress) or 200 (OK) response to S-CSCF with the modified SDP answer for the requested application data channel as well as the media descriptions of established video, audio, and bootstrap data channels after the receipt of an acknowledgement from the DCSF to the corresponding notification.

Upon receipt of a CANCEL request to the re-INVITE request, the IMS AS shall notify the DCSF about the media change cancellation, request the MF to release the corresponding data channel media resources and forward the CANCEL request to the S-CSCF towards the terminating UE.

Upon receipt of a 4xx, 5xx or 6xx response on the re-INVITE request from the terminating UE, the IMS AS shall notify the DCSF about media change failure, request the MF to release the corresponding data channel media resources and forward the response to the originating network.

Upon receiving the re-INVITE request from the terminating UE to setup an application data channels and the corresponding response form the originating network, the procedure in clause 9.3.2.2.2.2 applies.

9.3.3.2.2.3 Closing application data channel p. 21

Upon receipt of the re-INVITE request with an SDP offer which contains an existing application data channel media description in which the UDP port number is set to 0, the IMS AS shall notify the DCSF about media change request, and request the MF to release the corresponding media resource if the media instruction from DCSF is to delete the media.

Upon receipt of the re-INVITE request with an SDP offer which contains an existing application data channel media description in which an existing "a=dcmap" line is removed, the IMS AS shall notify the DCSF about media change request, and request MF to update the media resource if the media instruction from DCSF is to update the media.

Upon receipt of the 200 (OK) response on the re-INVITE message with the SDP answer, the procedure in clause 9.3.3.2.2.2 applies.

Upon receiving the re-INVITE request from the terminating UE to close an application data channels and the corresponding 200 (OK) response form the originating network, the procedure in clause 9.3.2.2.2.3 applies.

9.3.3.2.3 MMTel session release p. 24

Upon initiation or receipt of a BYE request matching an existing MMTel session with IMS data channel, the procedure defined in clause 9.3.2.2.3 applies.