I am trying to get a concrete confirmation with supporting documentation on how vms communicate to each other if residing on the same host. From what I have read on multiple threads:

'VM's will not use the physical NIC if the two VMs are on the same vSwitch.'

Here is my scenario: 2 node cluster




NETWORK: Physical NIC <-> NIC Team <-> (External) vSwitch <-> VM

So that I'm know I'm 100% correct.

ANY/ALL traffic, with an origin/destination, from/for, a VM residing on the same host server, using the same vSwitch, will traverse via that said vSwitch.


VMa <-> (External) vSwitch <-> VMb


VMa <-> (External) vSwitch <-> NIC Team <-> Physical NIC <-> NIC Team <-> (External) vSwitch <-> VMb

If I could get some supporting documentation for this that would be most helpful. I have had no luck finding it myself.


-HyperV Virtual - Layer 2 Device (Switch) -Physical NIC - ACT like Layer 3 Device (Router)

1.If your having two VM's in the same subnet and connected to same HyperV Virtual switch the communication between two virtual adapters will be like this

VM1 <-> HyperV Virtual <-> Physical NIC <-> VM2

2.If your having two VM's in the different subnet and connected to different HyperV Virtual switch the communication between two virtual adapters will be like this

VM1 <-> HyperV Virtual <-> Physical NIC <-> HyperV Virtual <-> VM2.

Note : Basically all VM's will be connected to HyperV Virtual switch using Virtual NIC's.

By default, Physical NIC is bounded to Management Network (Through which all communication and network commissioning and decommissioning happens)

In this scenario, if you have more than one VM you can connect all VM to Single HyperV Virtual switch (if all in the same subnet) or to Individual HyperV Virtual switch (for individual subnet).

Better go for individual virtual subnet setup if have more than one subnet to have better working and understanding.



The following link suggests differently: TechNet

Also, the Altaro link states:

Ethernet Frame Switching The Hyper-V virtual switch is able to read the MAC addresses in an Ethernet packet and deliver it to the correct destination if it is present on the virtual switch. It is aware of the MAC addresses of all virtual network adapters attached to it. An external virtual switch also knows about the MAC addresses on any layer-2 networks that it has visibility to via its assigned physical adapter or team.

Would this not suggest that no traffic would traverse the physical switch?

Both VMs are connected to the same vSwitch, are within the same subnet and reside on the same host?

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.