Networking Deployment Guide: Deploying High-speed Networking Features

Applies To: Windows Server 2008 R2

This guide is intended for IT professionals interested in using high-speed networking features that may improve network and operating system performance. The guide provides a conceptual overview of the features and their prerequisites, deployment instructions, and monitoring information. The following table summarizes availability of these features in Windows Server® 2008 and Windows Server® 2008 R2.

Operating System Available high-speed networking features

Windows Server 2008

TCP Chimney Offload

Receive Side Scaling


Windows Server 2008 R2

TCP Chimney Offload

Virtual Machine Queue

Receive Side Scaling



Many of these features were included for download as part of the Scalable Networking Pack in Windows Server 2003. With the release of Windows Server 2008, the features are included as part of the operating system. Information in this guide, except where specifically noted as applicable only to Windows Server 2008 R2, applies to servers running Windows Server 2008 as well. For more information about the Scalable Networking Pack in Windows Server 2003, see Scalable Networking on Microsoft TechNet.

Overview of high-speed networking features

High-speed networking features include the following:

  • TCP Chimney Offload. TCP Chimney Offload transfers TCP/IP protocol processing from the CPU to a network adapter during network data transfer. This feature was also available in Windows Server 2008. Windows Server 2008 R2 added an automatic mode and includes new performance monitor counters.

  • Virtual Machine Queue (VMQ). This is a new feature in Windows Server 2008 R2. VMQ provides scalability for virtual networks by distributing received frames into different queues based on the target VM. On a multiprocessor computer, these queues can be processed by different CPUs. VMQ can also use hardware packet filtering to reduce the overhead of routing packets to the virtual machine. To use this feature, VMQ must be supported by the network hardware.

  • Receive Side Scaling. Receive Side Scaling allows the load from a network adapter to be distributed across multiple CPUs in a multiprocessor computer. This feature was available in Windows Server 2008. In Windows Server 2008 R2, improvements were made in initialization and CPU selection at startup, registry keys for tuning performance were added, and new performance counters were added.

  • NetDMA. NetDMA provides offloading of the memory copy operation that is performed by the networking subsystem when receiving network packets to a dedicated DMA engine. This feature was available in Windows Server 2008. No changes were made for Windows Server 2008 R2.

See Also


Using TCP Chimney Offload
Using Virtual Machine Queue
Using Receive Side Scaling
Using NetDMA