Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

This paper describes the fundamental components of quality of service (QoS) and how they can be supported through various solutions based on the Internet protocol (IP). We consider and contrast the QoS efforts undertaken by the Internet Engineering Task Force (IETF) in the Integrated Services and Differentiated Services working groups. We then describe the integrated services model, evaluate differentiated services, and discuss how the latter is expected to evolve.

The purpose of this document is to define an information model to describe the quality of service (QoS) mechanisms inherent in different network devices, including hosts. Broadly speaking, these mechanisms describe the properties common to selecting and conditioning traffic through the forwarding path (datapath) of a network device. This selection and conditioning of traffic in the datapath spans both major QoS architectures: Differentiated Services and Integrated Services. This document should be used with the QoS Policy Information Model (QPIM) to model how policies can be defined to manage and configure the QoS mechanisms (i.e., the classification, marking, metering, dropping, queuing, and scheduling functionality) of devices. Together, these two documents describe how to write QoS policy rules to configure and manage the QoS mechanisms present in the datapaths of devices.