This clause describes the architecture for enabling edge applications in the following representations:
A service-based representation, where the Edge Enabler Layer functions (e.g. ECS) enable other authorized Edge Enabler Layer functions (e.g. EES) to access their services. This representation also includes point-to-point reference points where necessary;
A service-based representation as specified in TS 23.501, where the Network Functions (e.g. NEF) enable authorized Edge Enabler Layer functions (e.g. ECS) i.e. Application Functions, to access their services;
A service-based representation, where the Core Network Northbound APIs as specified in TS 23.501 and TS 23.502, are utilized by authorized Edge Enabler Layer functions via CAPIF core function specified in TS 23.222; and
A reference point representation, where existing interactions between any two functions (e.g. EES, ECS) is shown by an appropriate point-to-point reference point (e.g. EDGE-6, EDGE-7).
Edge Enabler Layer functions shown in the service-based representation of the edge architecture shall only use service-based interfaces for their interactions.
Figure 6.2-1 illustrates the service based representation of architecture for enabling edge applications.
The ECS, EES and EAS acts as AFs for consuming network services from the 3GPP 5G Core Network entities over the Service Based Architecture specified in TS 23.501.
Figure 6.2-3 illustrates the service-based representation for utilization of the Core Network (5GC, EPC) northbound APIs via CAPIF.
The ECS, EES and EAS act as authorized API invoker to consume services from the Core Network (5GC, EPC) northbound API entities like SCEF, NEF, SCEF+NEF which act as API Exposing Function as specified in TS 23.222.
The mechanism for northbound APIs discovery using the service-based interfaces depicted in Figure 6.2-3 is as specified in TS 23.222.
Figure 6.2-4 illustrates the reference point representation of the architecture for edge enabling applications.
The EDN is a local Data Network. EAS(s) and the EES are contained within the EDN. The ECS provides configurations related to the EES, including details of the EDN hosting the EES. The UE contains AC(s) and the EEC. The EAS(s), the EES and the ECS can interact with the 3GPP Core Network. When SEAL notification management service is used, the EES and the ECS interacts with the SEAL notification management server and the SEAL EEC interacts with SEAL Notification management client.
EES provides supporting functions needed for EASs and EEC.
Functionalities of EES are:
provisioning of configuration information to EEC, enabling exchange of application data traffic with the EAS;
providing API invoker and API exposing functions as specified in TS 23.222;
interacting with 3GPP Core Network for accessing the capabilities of network functions either directly (e.g. via PCF) or indirectly (i.e. SCEF/NEF/SCEF+NEF);
exposing events related to ACT;
EEC context transfer between EESs;
supporting external exposure of 3GPP network and service capabilities to the EAS(s) over EDGE-3;
registration functions (i.e., registration, update, and de-registration) for the EEC(s) and the EAS(s);
triggering the EAS instantiation on demand; and
supporting ACR related operations (e.g. ACR launching, ACR information notification, EELManagedACR).
ECS provides supporting functions needed for the EEC to connect with an EES.
Functionalities of ECS are:
provisioning of Edge configuration information to the EEC. The Edge configuration information includes the following:
the information for the EEC to distinguish amongst the EESs (e.g. EDN service area); and
the information for establishing a connection with EESs (such as URI);
providing the T-EES information to the S-EES;
supporting the functionalities of registration (i.e., registration, update, and de-registration) for the EES(s);
supporting the functionalities of API invoker and API exposing function as specified in TS 23.222; and
interacting with 3GPP Core Network for accessing the capabilities of network functions either directly (e.g. via PCF) or indirectly (i.e. SCEF/NEF/SCEF+NEF).
AC is the application resident in the UE performing the client function. Depending on how ACR is implemented, the AC might be required to decide whether to initiate ACR. Other details of the AC are out of scope of this specification.
EAS is the application server resident in the EDN, performing the server functions. The AC connects to the EAS in order to avail the services of the application with the benefits of Edge Computing.
It is possible that the server functions of an application are available only as an EAS.
However, it is also possible that certain server functions are available both at the edge and in the cloud, as an EAS and an Application Server resident in the cloud respectively. The server functions offered by an EAS and its cloud Application Server counterpart may be the same or may differ; if they differ, the Application Data Traffic exchanged with the AC may also be different.
The EAS can consume the 3GPP Core Network capabilities in the following ways, all of which are optional to support:
invoking 3GPP Core Network capabilities via the edge enabler layer through the EES
invoking 3GPP Core Network function (e.g. PCF) APIs directly, if it is an entity trusted by the 3GPP Core Network; and
invoking the 3GPP Core Network capabilities through the capability exposure functions i.e. SCEF/NEF/SCEF+NEF.
The EAS can support processing ACR related operations (e.g. ACR status update, selected target EAS declaration).
The EAS can expose its Service API(s) (i.e., EAS Service API(s)) towards the other EASs by supporting API provider domain functions as specified in TS 23.222; and the EAS can consume the EAS Service API(s) exposed by the other EAS(s) by supporting API invoker functionalities as specified in TS 23.222.
EDGE-2 reference point enables interactions between the EES and the 3GPP Core Network functions and APIs for retrieval of network capability information. It supports:
EDGE-7 reference point enables interactions between the EAS and the 3GPP Core Network functions and APIs for retrieval of network capability information. It supports:
EDGE-8 reference point enables interactions between the ECS and the 3GPP Core Network functions and APIs for retrieval of network capability information. It supports:
EDGE-9 reference point enables interactions between two EESs. EDGE-9 reference point may be provided between EES within different EDN (Figure 6.5.10-1) and within the same EDN (Figure 6.5.10-2).
The cardinality rules are applied to the architecture specified in clause 6.2. The cardinality rules are classified as functional entity cardinality and reference point cardinality. The functional entity cardinality specifies the multiplicity of the functional entity that can exist as per the architecture. The reference point cardinality specifies the multiplicity of source and target functional entities that can exist in a relationship defined by the reference point in the architecture.
Capability exposure includes the 3GPP core network (i.e. 5GC, EPC), ECS and the EES capability exposure, to fulfil the needs of the edge service operations. The capability exposure functionality is utilized by the functional entities (i.e. EES, EAS and ECS) depicted in the architecture for enabling the edge applications.