Traffic control services in Windows 2000 are used to manage traffic flow for QoS-aware and non QoS-aware programs. For programs that are not QoS-aware, traffic that they generate uses the traffic control API (TCI). This traffic is considered best effort and is sent to the TCP/IP stack. Traffic that is generated from a QoS-aware program uses the GQoS (Generic QoS API), with the intent of setting up a bandwidth reservation. When this QoS-aware traffic reaches TCI, TCI carries out the traffic control already implemented in the (RSVP) packet.

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Traffic Control Components

Packet Scheduler

The Packet Scheduler assumes the duty of traffic policing, because it basically determines whether a particular flow can be admitted entry to the network. It determines the delivery schedule of each packet queue and handles competition between queued packets that need simultaneous access to network resources. The packet scheduler takes the information from the packet classifier, creates queues for each data flow, and then empties the queues at the rate specified by RSVP when the flow was created.

Packet Classifier

Packet Classifier maps each incoming packet to a specific priority level, so that these levels may be acted on individually to deliver traffic differentiation. Once the packets have been queued by priority level, Packet scheduler services them accordingly.

Admission Control

Admission Control determines whether a flow can be granted without disrupting any established flows in the network.

Resouce Reservation

RSVP (Resource Reservation Protocol) is used to set up a flow state between the end computers, as well as the inter-network devices along the data path.

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Installing QoS Packet Scheduler

To install QoS Packet Scheduler:

1.	Click Start, point to Settings, and then click Network and Dial-up Connections.
2.	Click the local area connection on which you want to install QoS Packet Scheduler, and then click Properties on the File menu.
3.	Click Install, click Service, and then click Add.
4.	Click QoS Packet Scheduler, and then click OK.

For related information, please see the following article in the Microsoft Knowledge Base:

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