Target Edge Enabler Server

Description

The Target Edge Enabler Server (T-EES) is a critical architectural component within the 3GPP Edge Application Enablement framework defined from Release 17 onwards. It functions as the server-side counterpart to the Edge Enabler Client (EEC), which resides in the User Equipment (UE) or an application server. The primary role of the T-EES is to serve as a trusted discovery and connection broker for edge applications. When an EEC seeks to utilize an edge computing service, it queries the T-EES. The T-EES, leveraging network capabilities and policies, provides the EEC with the necessary information to connect to the most appropriate Edge Application Server (EAS), which hosts the actual application logic. This process is governed by the Edge Configuration Server (ECS), which provisions the EEC with the address of the T-EES.

Operationally, the T-EES interfaces with other key network functions, including the Network Exposure Function (NEF) and the Unified Data Management (UDM), to access network and user data for making intelligent edge service selection decisions. It supports service APIs defined in 3GPP TS 23.558, allowing for application context transfer and seamless service continuity as a user moves. The T-EES is instrumental in implementing the 'EDGE-9' reference point, which is the interface between the EEC and the T-EES for service registration, discovery, and connectivity establishment.

From a deployment perspective, the T-EES can be located within the operator's network, potentially at a central site or distributed across multiple edge locations. Its implementation enables the network to dynamically steer application sessions to edge resources based on real-time conditions like UE location, network load, and application requirements. This decouples the application's need for low latency and high bandwidth from the core network's traditional centralized architecture, paving the way for a new generation of immersive and responsive services like augmented reality, industrial automation, and intelligent video analytics.

Purpose & Motivation

The T-EES was created to address the fundamental challenge of efficiently exposing and managing edge computing resources in a mobile network. Prior to its standardization, deploying low-latency applications at the network edge was often a bespoke, non-interoperable endeavor. Applications had no standardized mechanism to dynamically discover where edge resources were available or to establish optimal connections to them as users moved. This limited the scalability and commercial viability of edge computing.

The introduction of the T-EES in Release 17, as part of the broader Edge Application Enablement work item, provided a standardized, operator-controlled service enablement layer. It solves the problem of edge service discovery and access, ensuring that client applications can find and connect to the nearest or most suitable edge application instance in a secure and policy-controlled manner. This standardization is crucial for creating a multi-vendor ecosystem where application providers, network operators, and cloud providers can interoperate.

Furthermore, the T-EES enables new business models by allowing operators to expose edge capabilities as a service. It provides the necessary control plane functions to manage the lifecycle of edge application sessions, including aspects of security, mobility, and quality of service, which were previously difficult to orchestrate in a distributed edge environment. Its creation was motivated by the industry's shift towards distributed cloud architectures and the need to support ultra-reliable low-latency communication (URLLC) and enhanced mobile broadband (eMBB) use cases that are impractical with a purely centralized core network.