If you've deployed your ISA Server, Microsoft IAG, Forefront TMG or Forefront UAG 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:

http://support.microsoft.com/kb/974909

Thanx to the Hyper-V team for this update!

 Jim Harrison, Program manager, FF Edge CS