Differentiated Services in the Internet

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The phrase "Quality of Service" (QoS) has been used frequently, with a variety of different meanings, in recent discussion of the Internet. In this paper we use it in a relatively narrow sense, to describe a set of measureable parameters, such as delay, throughput, and loss rate that can be attached to some identifiable subset of the traffic of Internet Protocol (IP) packets through a given network domain. We expand on this point and emphasize that giving any sort of guarantee about the values of such parameters to a user requires the implementation and deployment of physical mechanisms throughout the network. Configuring these mechanisms in such a way that their effect, when viewed from the edges of the network, composes into the desired QoS for the user can be a complex matter.

A "user" of IP quality of service spans a range of granularities, from a single application program to an entire company. After reviewing the background to this problem, this paper motivates one particular approach to a solution, known as Differentiated Services. It gives a technical overview of this approach, discusses resource allocation and configuration questions, and gives some application examples, before concluding with a look at the future.

By: Brian Carpenter, Kathleen Nichols

Published in: IEEE Proceedings, volume 90, (no 9), pages 1479-94 in 2002


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