If the NRF is used for NF registration and discovery, the DCSF and the MF shall register their services at the NRF before providing services to consumers, and existing NRF based mechanism needs to be extended with DC specific profiles according to
clause 4.17.1 of TS 23.502.
The DCSF profile includes NF type=DCSF and may include IMPU ranges for calling identities or called identities of users it serves.
The DCSF can update and deregister in the NRF after registration and the procedures are specified in
clauses 4.17.2 and
4.17.3 of
TS 23.502.
After registration in the NRF, the DCSF can be discovered by other consumer NFs as specified in
clauses 4.17.4 and
4.17.5 of
TS 23.502.
The MF profile includes NF type=MF and may include MF location information to select a local MF to minimize transmission delays in the media path.
The MF can update and deregister in the NRF after registration and the procedures are specified in
clauses 4.17.2 and
4.17.3 of
TS 23.502.
After registration in the NRF, the MF and its services can be discovered by other consumer NFs as specified in
clauses 4.17.4 and
4.17.5 of
TS 23.502.
According to
clause 6.2.10.1 of TS 26.114, the UE can send a HTTP GET Request for the root (
"/") URL through the bootstrap data channel which is replied with a data channel application describing the graphical user interface and the logic needed to handle any further data channel usage beyond the bootstrap data channel itself. The graphical user interface can e.g. contain a menu of applications, from which the user can choose one or several. The graphical user interface should be subscriber specific and contain only applications for which the user has subscribed to and is authorized to use. To provide the graphical user interface containing subscriber specific data channel applications via the bootstrap data channel to the UE, the DCSF, when receiving a call event notification including subscriber specific information and optionally stream ID from the IMS AS, creates the URL identifying the graphical user interface corresponding to the stream ID (if available) for this subscriber.
When a bootstrap data channel is established successfully, the bootstrap data channel shall be kept available during the IMS MMTel session, and it shall be terminated along with the release of the call.
The application data channel shall be terminated along with the release of the call or be terminated by closing this application separately. In the latter case, the UE triggers a SDP negotiation to release the application data channel.
The termination of application data channel shall not have any impact on the audio or video within the IMS sessions.
The appropriate 5QI/QCI for the QoS flows of the IMS data channel media, as defined in
TS 26.114, shall be applied over the 5GS system or EPS system for IMS data channel.
To enable the use of MRF as media resource function for IMS DC, there is a need to map the MF MRM SBI services, operations, and attributes to Mr'/Cr requests and responses.
Table AC.7.8-1 defines a high level mapping between MF MRM SBI services, operation and Mr'/Cr Requests: