QOS Events

Windows 2000 QOS makes certain information available to applications that register interest in obtaining event-related QOS information. Windows 2000 QOS makes the following event categories available to applications:

• Policy-based or administratively-based information that impacts QOS provisioning for a given flow.
• Errors that occur upon setup, or during the life of a QOS-enabled flow
• Information regarding acceptance or rejection of QOS requests by the RSVP module or by the network. Keep in mind that rejection of a QOS request may indicate a transient failure, which may be subsequently corrected.
• Significant changes in the service quality provided by the network (when in contrast with previously negotiated QOS parameters), such as from flow preemption in the network.
• Status regarding the presence of a QOS peer to send or receive a particular flow.

Windows 2000 QOS provides this status information through the FD_QOS event suite. Applications that take advantage of QOS capabilities, whether sending or receiving data, should use FD_QOS events to maintain and monitor their QOS-enabled application. Registering interest in QOS events is done by listening for FD_QOS event notifications.

It is important to realize that all FD_QOS events are edge-triggered. With edge-triggered events, a message is posted exactly once when a QOS change occurs. Further messages are not forthcoming until the provider detects a further change in quality of service, or the application re-negotiates the flow's quality of service.

For more information about event notification, consult the following Knowledge Base article:

support.microsoft.com/support/kb/articles/Q196/3/60.ASP