5C Data formats

24.3713GPPProtocol specificationRelease 16Stage 3TSWeb Real-Time Communications (WebRTC) access to the IP Multimedia (IM) Core Network (CN) subsystem (IMS)

5C.1 General

Data format is codec specifications, format specifications and functionality specifications for the data passed between systems. audio and video codecs, as well as formats for data and document sharing, belong in this category.

5C.2 UE

A UE supporting WebRTC shall support the WebRTC non-browser functionality as specified in RFC 8825 [30] clause 6, excluding requirements to implement specific audio and video codecs.

A UE offering WebRTC access to the IMS via GPRS IP-CAN (as described in 3GPP TS 24.229 [3], annex B), EPS IP-CAN (as described in 3GPP TS 24.229 [3], annex L), or EPC via WLAN IP-CAN (as described in 3GPP TS 24.229 [3], annex R) shall support the speech codecs according to 3GPP TS 26.114 [34] clause 5 and the front-end handling as specified in 3GPP TS 26.114 [34] clause 11.

A UE offering WebRTC access to the IMS via xDSL, Fiber or Ethernet IP-CAN (as described in 3GPP TS 24.229 [3], annex E) shall support the speech codecs according to 3GPP TS 26.114 [34] clause 18.

A UE supporting WebRTC access to the IMS via GPRS IP-CAN (as described in 3GPP TS 24.229 [3], annex B), EPS IP-CAN (as described in 3GPP TS 24.229 [3], annex L), or EPC via WLAN IP-CAN (as described in 3GPP TS 24.229 [3], annex R) and supporting video communication shall support the video codecs according to 3GPP TS 26.114 [34].

A UE supporting WebRTC access to the IMS via xDSL, Fiber or Ethernet IP-CAN (as described in 3GPP TS 24.229 [3], annex E) and supporting video communication shall support the video codecs according to 3GPP TS 26.114 [34] clause 18.

NOTE: Media related requirements related to specific codecs, if any, to be supported by a UE supporting WebRTC access to the IMS via IP-CAN other than GPRS IP-CAN, other than EPS IP-CAN, other than EPC via WLAN IP-CAN and other than xDSL, Fiber or Ethernet IP-CAN are out of scope of this specification.

5C.3 WWSF (WebRTC Web Server Function)

There are no data format requirements for the WWSF.

NOTE: Any application downloaded from the WWSF that requires data formats is expected to use it in accordance with WebRTC non-browser support of data formats.

5C.4 eP-CSCF (P-CSCF enhanced for WebRTC)

The eP-CSCF and eIMS-AGW in conjunction shall support the WebRTC gateway functionality as specified in RFC 8825 [30] clause 6, excluding requirements to implement specific audio and video codecs.

An eP-CSCF and eIMS-AGW supporting UEs offering WebRTC access to the IMS via GPRS IP-CAN (as described in 3GPP TS 24.229 [3], annex B), EPS IP-CAN (as described in 3GPP TS 24.229 [3], annex L), or EPC via WLAN IP-CAN (as described in 3GPP TS 24.229 [3], annex R) shall support the codecs according to 3GPP TS 26.114 [34] clause 5.

An eP-CSCF and eIMS-AGW supporting UEs offering WebRTC access to the IMS via xDSL, Fiber or Ethernet IP-CAN (as described in 3GPP TS 24.229 [3], annex E) shall support the codecs according to 3GPP TS 26.114 [34] clause 18.

An eP-CSCF receiving an SDP offer from the IMS core network should retain the received codecs in the SDP offer it sends towards the UE to avoid transcoding.

NOTE: Media related requirements related to specific codecs, if any, to be supported by a eP-CSCF supporting WebRTC access to the IMS via IP-CAN other than GPRS IP-CAN, other than EPS IP-CAN, other than EPC via WLAN IP-CAN, and other than xDSL, Fiber or Ethernet IP-CAN are out of scope of this specification.