Policy-based QOS allows IT administrators to apply QOS to applications (which do not need to have native support for QOS), computers, and users in their enterprise network. qWAVE is designed to estimate the network bandwidth, intelligently mark the application packets (with proper DSCP values), and interact with the application in the event of network congestion or bandwidth fluctuations (informing the application to take appropriate actions). In Windows Vista, two features were introduced: Quality Windows Audio Video Experience (qWAVE) and policy-based QOS. Applications that set Layer 2 priorities for their traffic had to implement an independent service with administrative privileges to set Layer 2 priorities using TC APIs. In Windows XP Service Pack 2 (SP2), the GQOS mechanisms allowed the application to set Layer 3 priorities only. The QOS mechanisms provided in Windows XP supported enterprise QOS needs for wired networks. The TC API provided control of QOS mechanisms (such as prioritization and shaping) at the host level rather than at the application level, but it required administrative privileges to be invoked. The kernel component that implemented prioritization and traffic shaping was the QOS Packet Scheduler, called the Traffic Control (TC) API. Although GQOS continued to be the application interface for accessing prioritized QOS, the reservation mechanisms had been removed. In Windows XP, the focus was on prioritization and traffic shaping mechanisms. Windows 2000 also provided tools, such as Subnet Bandwidth Manager (SBM) and QOS policy control. The GQOS API provided access to QOS mechanisms that were available as part of the networking stack. Windows 2000 introduced the Generic QOS (GQOS) application programming interface (API) as a framework for QOS. Shape and smooth the traffic that clients submit to the network, thereby avoiding the overburdening of switches and routers suffered with traditional burst transmissions.Reserve portions of a given bandwidth for applications or users that require such availability for core business activities.Control network device resources based on user policy and/or application usage.Give applications their required bandwidth - provided bandwidth availability exist.Specify or request bandwidth requirements particular to their application, such as latency requirements for streaming audio.The goal of Quality of Service (QoS) is to provide preferential treatment to certain subsets of data, enabling that data to traverse the traditionally best-effort Internet or intranet with higher quality transmission.

Qos packet scheduler service