Vertical Application Layer Client

Description

VAL (Vertical Application Layer) client is a functional entity defined in 3GPP specifications, particularly in TS 23.434 and TS 23.700. It provides the client-side functionalities corresponding to vertical applications, which are industry-specific applications that leverage 3GPP network capabilities. The VAL client resides in the UE (User Equipment) and interacts with the VAL server, which is typically located in the network or at the edge. The VAL architecture is designed to provide a common framework for vertical applications, enabling interoperability and reuse of 3GPP enablers such as group communication, location services, and QoS management.

The VAL client is part of the Vertical Application Layer (VAL) architecture, which is specified in 3GPP TS 23.434. The VAL architecture defines a set of common services and enablers that can be used by different vertical industries. The VAL client is the counterpart to the VAL server, and together they provide the application-level functionality. The VAL client communicates with the VAL server over the V1 reference point, which is an application-level interface. The VAL client may also interact with other 3GPP network functions, such as the Policy Control Function (PCF) and the Network Exposure Function (NEF), to request network services and policies.

The operation of the VAL client involves several key procedures: registration, authentication, authorization, and service invocation. The VAL client registers with the VAL server to indicate its presence and capabilities. It may be authenticated and authorized based on subscription data and policies. Once registered, the VAL client can invoke services provided by the VAL server, such as group communication, messaging, and location reporting. The VAL client also receives notifications and events from the VAL server, such as incoming messages or group invitations. The VAL client is responsible for handling the user interface and user interactions for the vertical application, while the VAL server handles the network-side logic and coordination.

Key components of the VAL architecture include the VAL client, the VAL server, the VAL user, and the VAL service. The VAL user is the end-user of the vertical application, who interacts with the VAL client. The VAL service is the set of functionalities provided by the vertical application. The VAL client and VAL server together implement the VAL service. The VAL architecture also defines the VAL enablers, which are reusable service components that can be used by multiple vertical applications. Examples of VAL enablers include the Group Management enabler, the Location Management enabler, and the Communication enabler.

The VAL client is important because it provides a standardized way for vertical applications to access 3GPP network capabilities. By using the VAL client, vertical industries can develop applications that are interoperable and can leverage the advanced features of 5G networks, such as ultra-reliable low-latency communication (URLLC), enhanced mobile broadband (eMBB), and massive machine-type communication (mMTC). The VAL client also enables network operators to expose their capabilities to vertical industries in a controlled and secure manner, fostering innovation and new business models.

Purpose & Motivation

The VAL client was created to address the need for a standardized framework for vertical applications in 3GPP networks. Prior to the introduction of VAL, vertical industries had to develop their own proprietary solutions to access network capabilities, leading to fragmentation and lack of interoperability. The VAL architecture provides a common set of enablers and interfaces that can be used by different vertical industries, reducing development effort and enabling cross-industry collaboration.

The motivation for the VAL client is to enable vertical applications to leverage the advanced capabilities of 5G networks, such as network slicing, edge computing, and QoS management, in a standardized way. By providing a client-side entity that interacts with the network through well-defined interfaces, the VAL client allows vertical applications to request and receive network services without needing to understand the underlying network complexities. This abstraction is essential for industries that are not telecom experts, such as automotive, manufacturing, and media.

Historically, the VAL architecture was introduced in 3GPP Release 17 as part of the work on 5G vertical applications. It builds on earlier enablers such as Mission Critical Push-to-Talk (MCPTT) and Vehicle-to-Everything (V2X) communication. The VAL client is a key component of this architecture, providing the client-side functionality that enables vertical applications to interact with the network. In Release 19 and 20, the definition of VAL client has been refined to be more concise, reflecting the maturity of the specification and the need for clarity.