Service Execution Environment

Description

The Service Execution Environment (SEE) is a concept defined in 3GPP TS 21.905, TS 22.121, and TS 22.127. It refers to a platform that provides a secure and controlled environment for executing applications or programmes, with specific authorisations to perform certain functionalities. The SEE can be implemented in various entities, such as the User Equipment (UE), the Integrated Circuit Card (ICC, e.g., SIM/USIM), or a network platform/server. The SEE provides the necessary APIs, runtime environment, and security mechanisms to allow applications to access network services and resources in a controlled manner. In the context of the UE, the SEE could be the operating system or a middleware layer that hosts applications and manages their permissions. For the ICC, the SEE is the smart card platform that runs applets (e.g., SIM Toolkit applications) and enforces access control to card resources. In the network, the SEE could be an application server or a service capability server that hosts applications and exposes network capabilities via APIs (e.g., via the Service Capability Exposure Function in 5G). The SEE concept is closely related to the Open Service Access (OSA) and the Service Capability Server (SCS) in earlier releases, and to the Network Exposure Function (NEF) in 5G. The SEE enables the deployment of value-added services by third-party application providers, while ensuring that the network's integrity and security are maintained. It provides a standardized way for applications to interact with network services, such as location, messaging, and charging. The definition has evolved slightly in wording but the core concept remains: a platform that authorises and executes applications with specific functionalities. The SEE is a key enabler for the Internet of Things (IoT) and machine-to-machine (M2M) communications, where devices and applications need to interact with the network in a secure and controlled manner.

Purpose & Motivation

The Service Execution Environment was introduced to provide a standardized framework for hosting and executing applications that need to interact with mobile network services. In the early days of 3GPP, as mobile networks evolved beyond voice, there was a need to open up network capabilities to third-party developers while maintaining security and control. The SEE addresses this by defining a platform that can authorise applications to perform specific functionalities, such as accessing location information, sending messages, or initiating calls. It solves the problem of how to securely expose network APIs to external applications without compromising the network. The SEE also provides a consistent execution environment across different devices and network entities, enabling portability of applications. For example, a SIM Toolkit applet runs in the ICC's SEE, while a network-based application runs in a server's SEE. This abstraction allows developers to write applications that can work across various environments. The concept has been foundational for subsequent developments like the Service Capability Exposure Function (SCEF) in 4G and the Network Exposure Function (NEF) in 5G, which further standardize the exposure of network services to applications. The SEE's purpose is to balance innovation and security, enabling a vibrant ecosystem of mobile applications while protecting the network and user data.