Using Virtual Machine Chimney

Applies To: Windows Server 2008 R2

Virtual Machine Chimney, which is new in Windows Server 2008 R2, enables virtual machines running within the Hyper-V server role to benefit from the TCP Chimney Offload feature. Virtual Machine Chimney can offload external virtual network processing from multiple virtual network adapters to a physical network adapter on the management operating system. When Virtual Machine Chimney makes TCP Chimney Offload available to virtual machines, the management operating system can also use TCP Chimney Offload for normal network traffic. Offload processing for virtual adapters is not prioritized; processing is offloaded on a first-come, first-served basis.


An external virtual network is a virtual network that connects virtual machines to physical networks by using a physical network adapter.

For a virtual machine to use TCP Chimney Offload, the virtual machine must be running Windows Server 2008 R2 or Windows 7 or, if running Windows Server® 2008 or Windows Vista®, the Integration Services Setup Disk must be installed on the virtual machine. TCP Chimney Offload is not available for virtual machines running earlier versions of the Windows operating system.

When you use Virtual Machine Chimney, you can use Netsh commands on the virtual machine to set the operational mode, to monitor, and to manage TCP Chimney Offload the same as you can on a non-virtualized operating system.

See Also


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