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).

Does Mikrotik plan to add the 5 Gbps setting?

Ubiquiti UF-RJ45-10G

According to reviews,this one doesnt support 2.5/5G

SwOS 2.17

Does it work in RouterOS?

CRS309 / CRS317

according to the datasheets, these CRS only support 1.25/10G. But I have no idea

EDIT: nvm apparently the CRS do support that and the datasheets are just old

@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.

Perhaps someone from Mikrotik can comment on this officially?

Only if you open support ticket with Mikrotik ... e.g. by sending e-mail to support@mikrotik.com .

Out of the blue, I assume you use the latest 2.17 SWOS.

In the interface tab there is a checkmark for sfp high/low pin, that doesnt affect which speeds gets available of the transceiver?

Hi,

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)