The 3G IP Multimedia Subsystem (IMS): Merging the Internet and the Cellular Worlds, Second Edition

Architectures for Internet quality of service (QoS) have been under discussion for over a decade and, with the commercialization of the Internet, the topic has become increasingly important. This paper gives a background and history of QoS for the Internet, then introduces and motivates the differentiated services (Diffserv) approach. The major advantages of the Diffserv approach are that it is a good match to the Internet architecture and that it can be initially deployed with a minimalist approach, adding complexity as needed. Despite the long history of discussion, the phrase "quality of service" does not have a universally accepted meaning. In this paper QoS is used to describe a set of measurable parameters, such as delay, throughput, and loss rate, that can be attached to some identifiable subset of the traffic of IP packets through a given network domain. The identifiable subset of traffic belongs to a "user" of IP QoS where "user" spans a range of granularities, from a single application program to an entire company. Providing guarantees about the values of network parameters requires the implementation and deployment of physical mechanisms throughout the network and then configuring these mechanisms in such a way that their effect, when viewed from the edges of the network, composes into the desired QoS. Diffserv uses simple mechanisms in a more complex composition, allowing the details of the composition to evolve while the mechanisms, part of the network infrastructure, can remain the same. The paper discusses the specifics of this approach and why it is well-matched to the Internet. Some practical issues for deployment are addressed. Further we address resource allocation and configuration questions, including simple possibilities for early deployment and some of the open questions for a more complex future deployment. This paper takes the position that it is possible to maintain reasonable QoS levels without recourse to any of the class of constrained routing approaches (including MPLS), though Diffserv can be used with these approaches if desired.

Differentiated services in the Internet

This document describes a Policy Information Base (PIB) for a device implementing the Differentiated Services Architecture. The provisioning classes defined here provide policy control over resources implementing the Differentiated Services Architecture. These provisioning classes can be used with other none Differentiated Services provisioning classes (defined in other PIBs) to provide for a comprehensive policy controlled mapping of service requirement to device resource capability and usage.

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Differentiated Services Quality of Service Policy Information Base

A system for providing a high communications quality is provided The system comprises: (a) an input operable to receive a message from at least one of first and second network nodes 200 and 204, the first and second network nodes communicating with one another in a session and the message indicating a service problem with the session and (b) a statistic collection agent 248 operable to cause, in response to the message, at least one of the following operations: (i) reconfiguration of one or more attributes or resources in the network; (ii) variation of a sampling frequency of one or more session-related performance attributes associated with the network; (iii) alteration of the types of session-related performance attributes being collected regarding the network; and (iv) collection of session-related information from nodes other than the at least first and second network nodes

Instantaneous user initiation voice quality feedback

This memo describes an SMIv2 (Structure of Management Information version 2) MIB for a device implementing the Differentiated Services Architecture. It may be used both for monitoring and configuration of a router or switch capable of Differentiated Services functionality.

Management Information Base for the Differentiated Services Architecture

This document defines a set of PRovisioning Classes (PRCs) and textual conventions that are common to all clients that provision policy using Common Open Policy Service (COPS) protocol for Provisioning.

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Framework Policy Information Base

This document, the Structure of Policy Provisioning Information (SPPI), defines the adapted subset of SNMP's Structure of Management Information (SMI) used to write Policy Information Base (PIB) modules.

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S. Hahn

Papers

Differentiated Services Quality of Service Policy Information Base

Framework Policy Information Base

Structure of Policy Provisioning Information (SPPI)