Windows 10 doing automatic load balancing when two NICS are installed

Question

_{Thursday, February 1, 2018 2:11 AM}

1) I have two PC with Windows 10 pro with latest updates, each PC has 2 x 1Gb network card installed connected to two different switches.

I noticed lately that when performing file transfers, windows is doing automatic load balancing using the two NICS without any special setup of any kind.

2) 1 NIC is configured with a gateway address and is dedicated for internet transfers,

3) 1 NIC has no gateway but has a higher priority for local file transfers between the two PC's.

4) I DON'T have Network load balancing set up

5) I DON'T have NIC teaming configured on either PC's

6) the NIC cards are Intel and Realtek using their respective drivers,

7) when doing large file transfer between the two PC's initially only one network card will be handle all the traffic, then a few seconds later windows will split the load between the two network cards equally.

8) I have successfully reached speeds of up to 180MB/sec (1440Mbit) when transferring large files located on SSD.

I would like to know if its possible to disable this automatic load balancing in windows 10?

Some people might welcome this behavior but for me its a PITA as I am monitoring my internet usage exclusively on the internet NIC and if Windows is using it for local file transfers then my internet usage calculation is no longer accurate.

thanks

All replies (3)

_{Thursday, February 1, 2018 10:09 AM ✅Answered | 1 vote}

Hi Delta 313,

Your Windows 10 Pro client won't do  any kind of Nic teaming out of the box.

You need advanced drivers from NIC manufacturer to do this as this feature has been removed by Microsoft a few years ago. And it is hard to make it work this way !

What you probably see that explains more than 1Gbps throughput is SMB Multichannel which is activated by default on clients and servers. It is a feature of SMB3.

Therefore it will only affect file transfers, not the internet traffic you are monitoring.

You can disable this feature using powershell :

Set-SmbClientConfiguration -EnableMultiChannel $false

Alternatively you could also disable SMB3 protocol and force older SMB2.

Hope this helps.

Regards

_{Thursday, February 1, 2018 9:16 AM}

Hi,

After my search, I’m afraid we cannot do like that, Microsoft doesn’t have official tools to perform this task.

Thank you for understanding.

Best Regards,

Tao

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_{Thursday, February 1, 2018 10:18 PM}

Thanks! that did the trick, it was the SMB multichannel option that was enabled by default.

Now after disabling the option,  Windows 10 is back to only one NIC for the file transfers