Service
A GATT Service is an Attribute that forms collection of data and associated behaviors to accomplish a particular function or feature. In GATT, a service is defined by its service definition. A service definition may contain included services, mandatory characteristics, and optional characteristics.
Types
There are two types of services: primary service and secondary service. A primary service is a service that exposes functionality of this device. A primary service can be included by another service. Primary services can be discovered using Primary Service Discovery procedures. A secondary service is a service that should only be included from a primary service or another secondary service or other higher layer specification. A secondary service is only relevant in the context of the entity that includes it.
Properties
The list of Characteristic this service supports
The list of Service that this service includes
The Type of the service