Traffic Control and Differentiated Services

Windows 2000 QOS is capable of providing differentiated services. The traffic control functionality built into Microsoft Windows 2000 QOS is also capable of operating in differentiated services mode. This capability is primarily used on routers, in which incoming IP packets are classified into generalized (differentiated) flows using the Diffserv code point (DSCP), rather than setting up and monitoring individual RSVP flows.

The packet scheduler component of TC can be put into differentiated services mode for a given interface by:

• Using TcSetInterface. Set GUID_QOS_ADAPTER_MODE to PSADAPTER_FLOW_MODE_DIFFSERV

The interface can be returned to its default mode of operation by setting the GUID to the default value of PSADAPTER_FLOW_MODE_STANDARD.

While operating in Diffserv mode, standard TC function calls, such as those found in the Traffic Control API (TC API) section are still used, but a special QOS object called QOS_OBJECT_DIFFSERV can be included with the TcAddFlow function call. This QOS object is used to specify the list of DSCPs that are used to classify incoming IP packets on a given flow. Hence the TcAddfilter function and TcDeleteFilter function will not be used for classifying packets.

For more information about QOS_OBJECT_DIFFSERV, see QOS Objects.