# Service components

The following components comprise a Natural Access service:

- Service API

- Service SPI

- Service implementation

- Service manager

The following illustration shows the Natural Access architectural model:

Natural Access service

The service interface component of a service includes the service API and the service SPI. The service implementation component includes the service manager and the service implementation.

Each service has a service name and service ID.

## Service name

Each Natural Access service is assigned a unique three letter acronym. This acronym is an integral part of the naming conventions for the components of a service. For example, the AG Board Driver Interface is referred to as the ADI service.

In this manual, the letters xxx are used to represent the three letter acronym assigned to a service.

## Service ID

Since Natural Access supports multiple services, any of which can be accessible to a client application, an internal mechanism is required to uniquely identify each service. This mechanism is the service ID.

The service ID is a 16 bit numeric value that is embedded in all command, error, and event messages. This allows the dispatcher to route messages between the service interface and the service implementation components.