Visited Edge Enabler Server

Description

The Visited Edge Enabler Server (V-EES) is a functional entity defined within the 3GPP Edge Application Enablement (EAE) framework, specified in TS 23.558. It resides in the visited Public Land Mobile Network (VPLMN) and serves as the primary service access point for roaming User Equipment (UE) seeking to utilize edge computing resources. Its core function is to facilitate the discovery, registration, and consumption of edge applications and services that are hosted in the visited network's edge data centers. The V-EES interacts with the Home Edge Enabler Server (H-EES) in the user's home network for authorization and service-level agreement (SLA) verification, ensuring that roaming users can access permitted edge services seamlessly.

Architecturally, the V-EES exposes a standardized Application Programming Interface (API) to client applications, known as Edge Enabler Clients (EECs), which may reside on the UE or within the application server. When a roaming UE requests an edge service, the EEC communicates with the V-EES. The V-EES, in turn, may query the H-EES via the EAE roaming interface to validate the user's subscription and service profile. Upon successful authorization, the V-EES provides the EEC with the necessary service configuration, including the endpoint address(es) of the target Edge Application Server (EAS) located in the visited network. This process ensures that user traffic is routed locally to the optimal edge node, minimizing latency and backhaul load.

The V-EES plays a critical role in the service continuity and performance for roaming scenarios. It manages the lifecycle of edge service sessions, handles potential service re-discovery due to UE mobility, and may collect usage data for charging purposes. By decoupling the service authorization (handled by H-EES) from the local service provisioning (handled by V-EES), the architecture supports both home-routed and local breakout service models for edge computing. Its implementation is key to realizing globally consistent, low-latency experiences for mobile users accessing demanding applications like augmented reality, industrial automation, or connected vehicle services while outside their home network coverage.

Purpose & Motivation

The V-EES was introduced to solve the challenge of providing efficient, low-latency edge computing services to roaming users. Prior to its standardization, edge services were primarily designed for users within their home network. Roaming users would either be unable to access local edge resources or would be forced to route their traffic back to their home network, incurring high latency and congesting core network links, which defeats the primary benefit of edge computing. This was a significant barrier for latency-critical applications like autonomous driving, real-time gaming, and extended reality (XR), which require consistent performance regardless of user location.

The creation of the V-EES, as part of the broader EAE framework in Release 18, was motivated by the commercial need for operators to offer advanced edge services on a global scale. It enables visited network operators to expose and monetize their edge infrastructure to roaming subscribers from partner operators. Technically, it addresses the problem of service discovery and access control in a multi-operator environment. Without a standardized visited-side entity like the V-EES, each operator pair would need bespoke integrations, stifling scalability. The V-EES provides the necessary anchor point in the visited network to authenticate roaming requests (via the home network), discover local edge application instances, and ensure compliant service delivery according to the user's home operator policies.