Quality of service terminology in IP networks

This article provides an overview of commonly used terminology related to quality of service assurance in IP networks. Several approaches to QoS definition, including those of IETF, ITU, and ETSI, are presented and compared. Terms associated with QoS like class of service, grade of service, service level agreement, as well as service level specification (SLS), traffic conditioning agreement (TCA), and traffic conditioning specification (TCS) are discussed. Terminology used in two QoS architectures, IntServ and DiffServ, is also introduced.