The network connection of a running Hyper-V virtual machine is lost under heavy outgoing network traffic on a Windows Server 2008 R2-based computer
If you’ve deployed your Virtual Machine on Hyper-V R2 and noticed that a connection between the guest and the virtual switch starts "acting odd", perfoms poorly or becomes disconnected entirely, you may want to apply this update:
To apply this hotfix, your computer must be running Windows Server 2008 R2.
Additionally, you must have Hyper-V role installed on your computer.
You have to restart the computer after you apply this hotfix