Quality of Service

Purpose

Quality of Service (QOS) is an industry-wide initiative to enable more efficient use of the network. The IETF has provided many documents in the form of Internet Drafts and RFCs that outline such capabilities, including those provided by the Intserv, Diffserv, ISSLL and RAP IETF working groups, among others. The goal of QOS is to provide preferential treatment to certain subsets of data, enabling such data to traverse the traditionally best-effort Internet or intranet with higher quality transmission service.

Quality of Service in Microsoft® Windows® 2000 is a collection of components that enable such differentiation, preferential treatment, and management of higher quality data transmissions across the network. The collection of QOS components included in Windows 2000 constitute the Microsoft Corporation implementation of the IETF vision of QOS.

Where Applicable

Developers can leverage knowledge of QOS to:

• Create or retrofit mission-critical applications that can operate as if network traffic conditions were ideal, even when the network is extremely congested.
  
  
• Create real-time applications, such as IP telephones or streaming multimedia, that receive transmission service that enable them to function as intended, without being at the mercy of traffic conditions at each hop along the network path between sender and receiver.
  
  
• Create or retrofit applications that are well-behaved network users, such that their network transmissions adhere to agreed-upon characteristics. By doing so, every corner of a QOS-enabled network becomes more manageable and more efficiently used, taming the traditional TCP approach of 'send all of it out as fast as possible,' and its associated effect on the clogging of network devices.

Windows 2000 Quality of Service achieves these capabilities through programmatic interfaces, the cooperation of multiple components, and communication with network devices throughout the end-to-end network solution.

Developer Audience

Programmable Quality of Service components are designed for use by C/C++ programmers. Familiarity with Windows networking and Windows Sockets 2 programming is required.

Run-time Requirements

Windows 2000 Quality of Service requires Windows 2000, and also has functionality for use on Windows 98 clients. For information on the limitations of implementing QOS-enabled applications on Windows 98, see Windows 98 QOS Notes in the Introduction to QOS section. Also, certain QOS functions require administrative privilege to execute; such component requirements are specified where appropriate.

See Also

Windows Sockets 2

Overview

General information about Quality of Service.

Reference

Documentation of QOS functions, structures, and objects.

Feedback

Make error reports and feature requests directly to Microsoft.