Vertical Application Layer

Description

The Vertical Application Layer (VAL) is a comprehensive service architecture specified by 3GPP, primarily in TS 23.434 and related specs. It is designed as an intermediary layer that sits between vertical industry applications (the clients) and the 3GPP network exposure functions (like NEF) or data network services. The VAL provides a vertical-specific abstraction of the underlying 5G network capabilities, data management, and device management services. Its architecture typically involves a VAL Server, VAL Clients (within vertical devices/sensors), and a VAL Management System.

The core functionality of VAL is to manage Vertical Application Layer Services (VAL Services). A VAL Service is a logical entity that represents a set of capabilities offered to a vertical application, such as group management for devices, data reporting and subscription, command delivery, or location tracking. The VAL defines standardized data models (e.g., for sensors, actuators, robots) and communication procedures using RESTful APIs, often leveraging HTTP/2 or MQTT. Key components include the VAL Service Management Function, which handles the lifecycle (creation, update, deletion) of VAL Services; the VAL Configuration Management, which provisions parameters to VAL Clients; and the VAL Data Management, which handles the storage, aggregation, and exposure of data collected from vertical devices.

How it works: A vertical application, such as a factory control system, interacts with the VAL Server via its APIs to create a VAL Service, for instance, a 'Robot Fleet Management Service'. The VAL Server then configures the relevant VAL Clients (software on the robots) with the service parameters. The robots (VAL Clients) use the VAL protocols to register, report telemetry data (like position, status), and receive commands from the application through the VAL Server. The VAL layer handles the translation between the application's intent and the necessary network actions. Crucially, it can interact with the 5G Core's Network Exposure Function (NEF) to request network capabilities like QoS guarantees for a specific robot group or the activation of a network slice tailored for the factory. This allows the vertical application to be largely agnostic to the specific 3GPP network implementation details while still leveraging advanced 5G features.

Purpose & Motivation

VAL was created to address the key challenge of integrating diverse and specialized vertical industry applications with the generic 5G system. Previous cellular generations were primarily designed for human-centric communication (voice, internet). 5G's promise to serve verticals like Industry 4.0, smart grids, and healthcare introduced a new set of requirements: ultra-reliable low-latency communication (URLLC), massive machine-type communication (mMTC), and precise network resource control. Without a standardized application layer, each vertical would need to develop custom, proprietary integrations with the 5G core, leading to complexity, high costs, and lack of interoperability.

The motivation for VAL in Rel-16 was to provide a common, 3GPP-standardized 'on-ramp' for verticals into the 5G network. It solves the problem of fragmentation by offering a uniform set of APIs and data models for verticals, shielding them from the underlying network complexity. This enables vertical application providers to develop once and deploy across different mobile network operators and countries. VAL also empowers network operators to expose and manage advanced 5G features (e.g., network slicing, edge computing, QoS) to vertical customers in a controlled, automated, and billable manner through a well-defined service layer. It is a critical enabler for the 5G business-to-business (B2B) and business-to-business-to-consumer (B2B2C) ecosystem, turning network capabilities into consumable services for industries.