The NDIS 6.0 Driver Model

NDIS 6.0 was introduced to the independent hardware vendor (IHV) and developer community at last year’s WinHEC. It brings the promise of greater performance, improved manageability, reduced complexity for NDIS miniports, and simpler models for writing intermediate and filter drivers. Are you curious how much of the promise has been realized?

At WinHEC this year, I’ll demonstrate network adapters which maximize network throughput with lower CPU utilization—all by moving to the NDIS 6.0 model. NDIS 6.0 miniport drivers have demonstrated 20% performance improvements over NDIS 5.1 miniport drivers!

Here are some examples of the feedback we’ve heard from some of our partners inside Microsoft, citing how NDIS 6.0 has made a difference in their scenarios.

Example 1: Pacer, the packet scheduling and shaping component of the Policy-based Quality of Service feature

The old Windows Packet Scheduler (PSched) was originally an NDIS 5.0 intermediate miniport. The new Windows Packet Scheduler (Pacer) uses the NDIS 6.0 lightweight filter model, resulting in better performance with lower overhead. In previous releases, enabling PSched in passive mode resulted in a 10% increase in CPU utilization. On Windows Vista, by contrast, enabling Pacer in passive mode results in an increase of only 0.5% in CPU utilization.

Example 2: Network Load Balancing (NLB)

The NLB development team told us that porting NLB from the intermediate miniport model to the lightweight filter model resulted in simpler code that was much easier to debug.

Example 3: Media Streaming and Interrupt Moderation

As the Quality of Service development team can attest, the OIDs for enabling and disabling interrupt moderation make a big difference in accurately measuring available bandwidth, which is key for smoother media streaming in home networks.

Want to see the improvements for yourself? Drop by the WinHEC Hardware showcase at the NDIS 6.0 booth to learn more about what the NDIS 6.0 model has to offer. Have questions for us on how the model works? Leave us a comment in response to this posting.

Aarti Bharathan

Program Manager, Core Networking