Hello,
With the availability of Realtek RTL8157 based USB network adapters, which can reach 5 Gbps, the problem now arises that under SwOS 2.17 (CRS309 / CRS317) this speed cannot be selected and auto-negotiation unfortunately does not work either.
I have tested all possible combinations. If both the USB adapter and the switch port are set to 2.5Gbps, the connection is established. With all others, the link does not come up. I tested this with Mikrotik S+Rj10 and Ubiquiti UF-RJ45-10G modules and the Delock USB-C to 5 Gigabit LAN adapter (81570).
@itimo01: Did you really read my post? 2.5 Gbps is working with both modules. But it is not possible to select 5 Gbps on SwOS.
According to the release notes, 2.5 G was added in version 2.16.
Perhaps someone from Mikrotik can comment on this officially?
BTW: RouterOS is too complicated for this application and the switches are in production.
I think the correct way to connect would be to set the link speed to 10G no Auto negotiation for the 10G RJ45 SFP+ ports in SWOS.
edit: Though on further testing (different RJ45 module though), Auto negotiation is also likely ok.
And a short ethernet cable, (to make sure that isn’t part of your problem)