Service attribute

Description

A service attribute is a fundamental concept in telecommunications service definition, representing a specified characteristic of a telecommunication service. This definition, sourced from ITU-T Recommendation I.112, has been adopted by 3GPP in specifications such as 21.905 (Vocabulary for 3GPP Specifications) and 22.060 (General Packet Radio Service (GPRS); Service description; Stage 1). Service attributes are used to describe the properties and requirements of a service in a structured and standardized manner. They enable service providers, network operators, and equipment vendors to unambiguously specify what a service does and how it should behave.

In the context of 3GPP networks, service attributes are essential for defining the characteristics of bearer services, tele-services, and supplementary services. For example, a service attribute might specify the maximum bit rate, the transfer delay, the error rate, or the traffic class. These attributes are used in service level agreements (SLAs), in the negotiation between the user equipment (UE) and the network, and in the configuration of network elements to ensure that the service is delivered as expected. The concept is closely related to Quality of Service (QoS) parameters, as many service attributes directly influence the QoS experienced by the user.

Service attributes are typically organized into sets or profiles that define a particular service. For instance, in GPRS, the QoS profile consists of attributes such as precedence class, delay class, reliability class, peak throughput class, and mean throughput class. Each attribute has a defined range of values and a default value. The network uses these attributes to allocate resources, schedule packets, and manage mobility. The attributes may be negotiated at session establishment and can be renegotiated during the session if the network supports it.

The definition of service attributes has remained stable across 3GPP releases from Rel-4 to Rel-19, reflecting its foundational nature. The term is used consistently in specifications dealing with service aspects, and its meaning is well understood in the industry. While the specific attributes and their allowed values have evolved with new technologies (e.g., 5G QoS characteristics), the concept itself remains unchanged. This stability underscores the importance of having a common vocabulary for service description, which is critical for interoperability between different networks and vendors.

In summary, a service attribute is a building block for describing telecommunication services. It allows the precise specification of service characteristics, facilitating service creation, provisioning, and assurance. Understanding service attributes is essential for anyone involved in the design, implementation, or operation of telecommunication networks, as they form the basis for service differentiation and QoS management.

Purpose & Motivation

The concept of service attributes exists to provide a standardized, unambiguous way to describe the characteristics of telecommunication services. Before such a concept was formalized, service descriptions were often ad-hoc and vendor-specific, leading to interoperability issues and difficulty in comparing services. The ITU-T I.112 definition, adopted by 3GPP, solves this by establishing a common vocabulary. It allows network operators to specify exactly what a service offers, enables equipment from different vendors to interoperate, and provides a basis for service level agreements. Service attributes are crucial for QoS management, as they define the parameters that the network must meet. They also facilitate service negotiation between the user and the network, ensuring that the user's requirements are communicated and met. The stability of this definition across releases highlights its fundamental role in telecommunications.