CableCreation USB3.0 2.5GbE Adapter (RealTek) $22.99 - 5% off coupon (clip) @ Amazon

[mxnerd]

Then what does?

You forgot the time when routers only have 100M WAN port but have Gigabit LAN ports?

 

[VirtualLarry]

No, I was speaking in the context of a PC host with a 1GbE and a 10GbE, both into a 10GbE switch, connecting to a server, also with a 1GbE and a 10GbE.

Is there some part of STP, that "guides" the higher-speed link? Or some OS-level function, that returns the connection through the same NIC as it receives it?

Barring that, I would think that the return path from the server, would come from the NIC set as the Default Gateway on the server. At least, that's how it appears to be for my QNAP and Asustor units running Linux. If I want a solid 2.5GbE-T link, I have to unplug the 1GbE-T NICs on the NAS, or set the default Gateway to the 2.5GbE-T labeled "external NIC".

 

[mxnerd]

Link speed has nothing to do with default gateway. default gateway only takes into action when you try to reach an IP address that's not in you LAN IP range, like browsing the internet, for one example.

https://support.microsoft.com/en-us/help/299540/an-explanation-of-the-automatic-metric-feature-for-ipv4-routes

How to change the priority order of network adapters on Windows 10

If you use multiple network adapters on your Windows 10 PC, in this guide, we'll show you the steps to prioritize each one in two different ways.

www.windowscentral.com

If Windows do not set interface metric automatically and correctly, you have to set it manually. The lower number, the higher priority.

==
No Linux experience.

But here is the link also about interface metric

How do I set the priority of network connections in Ubuntu?

If a Ubuntu 11.04 machine is connected to WiFi and 3G simultaneously, how do I set the priority to let the applications (browser etc.) to use WiFi first? If that's not available, it should use the...

superuser.com

==

What's the reason you connect 2 NICs to the same NAS? OS (Either Windows or Linux) will only pick one NIC anyway.

<== Oops. SMB 3.0 probably will take advantage of multiple NICs under certain conditions. Not sure, no experience either, if client & server support the protocol properly on a local LAN.

 

[Bull Dog]

FreeNAS file server has a single 10 GbE connection to the switch using an Intel X540-T2 NIC.

 

[Muadib]

FreeNAS file server has a single 10 GbE connection to the switch using an Intel X540-T2 NIC.

Did you turn jumbo frames on? I had a similar issue with my unraid server until I did that.