Content for  TS 33.127  Word version:  19.1.0

Edge computing is a concept, described in TS 23.501, that enables operator and 3rd party services to be hosted close to the UE's access point of attachment, to achieve an efficient service delivery through the reduced end-to-end latency and load on the transport network. An Edge Computing Service Provider (ECSP) is a mobile network operator or a 3rd party service provider offering edge computing service. Details of edge hosting environment, are outside the scope of 3GPP (see clause 4.1 of TS 23.558). For edge computing, it is essential that the Application Clients (ACs) are able to locate and connect with the most suitable application server available in the Edge Data Network (EDN), depending on the needs of the application. The edge enabler layer exposes APIs to support such capabilities. The edge computing capabilities supported by 3GPP are defined in TS 23.558. Figure 4.1-1 in clause 4.1 of TS 23.558 gives an overview of 3GPP edge computing. The EES (see clause 6.3.2 of TS 23.558) is a component of the edge enabler layer which facilitates communication between the Application Clients running on the UE and the EAS deployed on the EDN. This includes EAS discovery by the UE and application context transfer between EASs for service continuity. The ECS (Edge Configuration Server) is another component of the edge enabler layer providing supporting functions needed for the EEC to connect with an EES. Figure 6.2-1 in clause 6.2 of TS 23.558 shows the general architecture for enabling edge applications using a service-based representation. Figure 7.16.1-1 shows an edge computing network, where EDN owned/managed by a ECSP (Edge Computing Service Provider) is communicating with the PLMN operator mobile network, and connected via UPF. The EDN contains EAS, EES and ECS. The PLMN operator is responsible for the deployment of NG-RAN, 5GC including AMF, SMF, UPF and NEF. Other models such as where the PLMN operator is the ECSP are possible. The ECSP can have service agreement with one or more PLMN operators and may request the PLMN operators to connect EAS and EES with 5GC network functions.

The EES shall provide the IRI-POI function. Figure 7.16.2-1 gives a reference point representation of the LI architecture with EES as a CP NF providing the IRI-POI function for edge computing.

The LIPF present in the ADMF provisions the intercept information associated with the following target identities to the IRI-POI present in the EES:

• GPSI.
• EECID.

The IRI-POI in the EES shall generate xIRI when it detects the following specific events or information in both roaming and non-roaming situations:

• EEC registration (see clause 8.4.2 of TS 23.558).
• EAS discovery (see clause 8.5.2.2 of TS 23.558).
• EAS discovery subscription (see clause 8.5.2.3 of TS 23.558).
• EAS discovery notification (see clause 8.5.2.3 of TS 23.558).
• Application context relocation (see clause 8.8.3.4 of TS 23.558).
• Application context relocation information subscription (see clause 8.8.3.5 of TS 23.558).
• Application context relocation information notification (see clause 8.8.3.5 of TS 23.558).
• EEC context relocation (see clause 8.9 of TS 23.558).
• Start of interception with registered EEC.

The EEC registration xIRI is generated when the IRI-POI present in the EES detects that an EEC (Edge Enabler Client) has performed a registration, registration update or deregistration procedure with the EES for a target. The EAS discovery xIRI is generated when the IRI-POI present in the EES detects that an EEC has performed an EAS discovery request-response procedure with the EES for a target. The EAS discovery subscription xIRI is generated when the IRI-POI present in the EES detects that an EEC has subscribed, updated its subscription and unsubscribed for EAS discovery reporting for a target. The EAS discovery notification xIRI is generated when the IRI-POI present in the EES detects that an EES has notified the EEC about EAS discovery information for a target. The application context relocation xIRI is generated when the IRI-POI present in the EES detects that an EEC has performed an ACR (Application Context Relocation) procedure with the EES with "ACR Action" set to. "ACR initiation request" or "ACR determination request" for a target. The application context relocation information subscription xIRI is generated when the IRI-POI present in the EES detects that an EEC has subscribed, updated its subscription and unsubscribed for ACR information reporting for a target. The application context relocation information notification xIRI is generated when the IRI-POI present in the EES detects that an EES has notified the EEC about ACR information for a target. The EEC context relocation xIRI is generated when the IRI-POI present in the EES detects that an EEC context information has been exchanged between current serving EES (referred to as source EES in TS 23.558) and new serving EES (referred to as target EES in TS 23.558. The start of interception with registered EEC is generated when the IRI-POI present in an EES detects that interception is activated on the target UE which EEC has already registered to the EES.

5G Media Streaming (5GMS) is a concept described in TS 26.501 and is defined as the delivery of time-continuous media as the predominant media. Streaming points to the fact that the media is predominantly sent only in a single direction and consumed as it is received. Additionally, the media content may be streamed as it is produced, referred to as live streaming. If media content being streamed is already produced, it is referred to as on-demand streaming. The overall 5G Media Streaming Architecture is shown in Figure 4.1.1-2 of clause 4.1 of TS 26.501.

The 5GMS AF shall provide the IRI-POI function. Figure 7.17.2-1 gives a reference point representation of the LI architecture with 5GMS AF as a CP NF providing the IRI-POI function for 5G Media Streaming. A 5GMS AF that is edge-enabled shall support EES functionality. A UE may request edge processing for a streaming session from the EES embedded in the 5GMS AF. EES provides the IRI-POI function as specified in clause 7.16.

The LIPF present in the ADMF provisions the intercept information associated with the following target identities to the IRI-POI present in the 5GMS AF:

• GPSI.

The IRI-POI in the 5GMS AF shall generate xIRI when it detects the following specific events or information in both roaming and non-roaming situations:

• Service access information (see clause 4.2.3 of TS 26.501).
• Consumption reporting (see clause 5.6 of TS 26.501).
• Metrics reporting (see clause 5.5 of TS 26.501).
• Dynamic policy invocation (see clause 5.7 of TS 26.501).
• Network assistance (see clauses 5.9 and 6.5 of TS 26.501).
• Start of interception with already configured UE.

The service access information xIRI is generated when the IRI-POI present in the 5GMS AF detects that a 5GMS AF has sent service access information to the Media Session Handler in the target UE. Service access information consists of a set of parameters and addresses that are needed by a UE to activate the reception of a downlink media streaming session or the transmission on an uplink media streaming session, perform dynamic policy invocation, consumption reporting and/or metrics reporting, and request AF-based network assistance. The consumption reporting xIRI is generated when the IRI-POI present in the 5GMS AF detects that the Media Session Handler in the target UE has reported downlink media consumption to the 5GMS AF. The metrics reporting xIRI is generated when the IRI-POI present in the 5GMS AF detects that the Media Session Handler in the target UE has reported QoE metrics reports to the 5GMS AF. The dynamic policy invocation xIRI is generated when the IRI-POI present in the 5GMS AF detects that a Media Session Handler in the target UE requests a specific policy and charging treatment to be applied to a particular application data flow of a downlink or uplink media streaming session to the 5GMS AF. The network assistance xIRI is generated when the IRI-POI present in the 5GMS AF detects that the Media Session Handler in the target UE requests a bit rate recommendation from the 5GMS AF or requests a delivery boost during the ongoing media streaming session from the 5GMS AF. The unsuccessfulProcedure xIRI is generated when the IRI-POI present in the 5GMS AF detects an unsuccessful procedure or error condition for the Media Session Handler in the target UE. The start of interception with already configured UE xIRI is generated when the IRI-POI present in the 5GMS AF detects that interception is activated on the target UE that has already received the service access information for the configuration of its media streaming sessions from the 5GMS AF.

Network Data Analytics Function (NWDAF) is a 5G network function which analyses data collected from network functions, OAM and UEs via AF in the 5G System, and publishes the analytics results to subscribing data analytics consumers. The results could be a summary of statistical/historical data, or an attempt to predict future data values related to UEs which user consent is granted. NWDAF covers the following data analytics services related to a UE:

• Observed service experience as defined in clause 6.4 of TS 23.288.
• UE mobility as defined in clause 6.7.2 of TS 23.288.
• UE communication as defined in clause 6.7.3 of TS 23.288.
• Abnormal behaviour as defined in clause 6.7.5 of TS 23.288.
• Data volume dispersion as defined in clause 6.10 of TS 23.288.
• Relative proximity as defined in clause 6.19 of TS 23.288.
• PDU session traffic as defined in clause 6.20 of TS 23.288.

NWDAF covers additional services which are not UE related, and additional services which are UE related but not of interest from LI perspective. LI for these services is not defined in the present document.

The NWDAF shall provide the IRI-POI function. Figure 7.18.2-1 gives a reference point representation of the LI architecture with NWDAF as a CP NF providing the IRI-POI function. NWDAF provides a set of data analytics in the form of statistics and predictions to authorized NF consumers. This LI architecture is valid in non-roaming and roaming situations. In roaming situation, data analytics may be exchanged between the visited network and home network via NWDAFs with roaming exchange capability.

• For an outbound roaming UE, the NF consumer in the home network can retrieve analytics from the NWDAF present in the visited network.
• For an inbound roaming UE, the NF consumer in the visited network can retrieve analytics from the NWDAF present in the home network.

The LIPF present in the ADMF provisions the intercept information associated with the following target identities to the IRI-POI present in the NWDAF:

• SUPI.

The IRI-POI in the NWDAF shall generate xIRI when it detects the following specific events or information:

• Events subscription (see clauses 7.2.2 and 7.2.3 of TS 23.288).
• Events notification (see clause 7.2.4 of TS 23.288).
• Analytics info query (see clause 7.3.2 of TS 23.288).
• Roaming analytics subscription (see clauses 7.7.2 and 7.7.3 of TS 23.288).
• Roaming analytics notification (see clause 7.7.4 of TS 23.288).

The POI in the NWDAF shall report analytics only when the target SUPI is the single SUPI for which the analytics is run. The events subscription xIRI is generated when the IRI-POI present in the NWDAF detects that a request to subscribe/update subscription/delete subscription for UE related analytics events for a target UE has been received from a consumer NF. The UE related analytics events are listed in clause 7.18.1. The events notification xIRI is generated when the IRI-POI present in the NWDAF detects that the NWDAF notifies a NF consumer about analytics events related to a target UE. The analytics info query xIRI is generated when the IRI-POI present in the NWDAF detects that the NWDAF has received a query for an analytics event related to a target UE. The roaming analytics subscription xIRI is generated when the IRI-POI present in the RE-NWDAF detects that a request to subscribe/update subscription/delete subscription for analytics events for a target inbound roaming or outbound roaming UE has been received from a consumer NWDAF. The roaming analytics notification xIRI is generated when the IRI-POI present in the RE-NWDAF detects that the RE-NWDAF notifies a NWDAF consumer about analytics events related to a target UE.

Web Real-Time Communication (WebRTC) adds real-time communication to the browser with a focus on peer-to-peer communication. It enables multimedia interaction capabilities in web browsers on any platform without installing a specific plug-in or using a third-party application. WebRTC leaves the signalling plan to service developers, who are free to implement any call control protocol, e.g. SIP over secure WebSocket, XMPP (Extensible Messaging and Presence Protocol) over WebSocket, etc. The only requirement is that the session negotiation data be represented by the SDP (Session Description Protocol). WebRTC clients may have access to IMS through mediation functions for signalling and media. The enhanced P-CSCF (eP-CSCF) is the endpoint for the signalling connection from the WebRTC IMS Client (WIC) and is located in the operator network. The enhanced IMS-AGW (eIMS-AGW) is the endpoint for the media connection from the WIC. Figure U.1.2-1 of TS 23.228 gives an overview of WebRTC IMS architecture. The WebRTC Web Server Function (WWSF) is the initial point of contact in the Web that controls access to the IMS communications services for the user. It provides a web page, which is the user interface (UI) for the user. The WebRTC Authorisation Function (WAF) creates an authentication token for the user and deliver it to the WWSF. The WAF is used in the case of IMS registration scenario using Web Authentication and is not used in the case of IMS registration scenario using IMS Authentication.

The WWSF and eP-CSCF shall provide the IRI-POI function. Figure 7.19.2-1 gives a reference point representation of the LI architecture with WWSF and eP-CSCF as CP NFs providing the IRI-POI function for WebRTC access to the IMS. This LI architecture is valid in non-roaming situations.

The eP-CSCF shall adhere to all LI requirements pertaining to the P-CSCF in addition to the LI requirements pertaining to the support of WebRTC access to IMS. The IMS-AGW of the IMS LI architecture detects the media to be intercepted and generates the associated xCC.

The LIPF present in the ADMF provisions the intercept information associated with the following target identities to the IRI-POI present in the WWSF:

• IMPU.
• IMPI.
• NAI (i.e. Web Identity).

The LIPF present in the ADMF provisions the intercept information associated with the following target identities to the IRI-POI present in the eP-CSCF:

• IMPU.
• IMPI.

The IRI-POI in the WWSF shall generate the following xIRIs:

• WIC authorization.
• Start of interception with already authorized WIC.

The IRI-POI in the eP-CSCF shall generate the following xIRI:

• Encapsulated signalling message.

The WIC authorization xIRI is generated when the IRI-POI present in the WWSF detects that the WIC uses a Web identity in the form of an NAI to authenticate with the WWSF and obtains an authorization token. The start of interception with already authorized WIC xIRI is generated when the IRI-POI present in the WWSF detects that interception is activated on the target WIC that has already been authenticated using its Web identity. The encapsulated signalling message xIRI is generated when the IRI-POI present in the eP-CSCF detects that a signalling message (e.g. SIP over WebSocket, XMPP over WebSocket, etc) is received from, or sent to, a target WIC.