CRS309 SFP+ to HeX S SFP connection

Hi all,

I purchased a CRS309 which I’m planning to use as an aggregation switch, got it set up in a breeze with the latest RouterOS version and 10G links with a couple of Mikrotik and Ubiquiti switches working fine.

However, I dumbly assumed I could use a direct attach cable (specifically, the genuine Mikrotik one - XS+DA0001) to connect the CRS309 to an SFP port on a HeX S router.
Instead, there’s no link activity at all when connecting the HeX S SFP to any of the CRS309 SFP+ cages and the interface doesn’t come up.

I assume it boils down to the switch manufacturer whether to offer 1G capabilities over SFP+? Would the rate select setting on each of the SFP+ interface in RouterOS make any difference?

Googling for “sfp to sfp+ compatibility” brings a sea of results and no definitive answer eventually.

Thanks in advance.

Looks to me it should work. Have you tried setting speed & duplex to 1000/Full instead of Auto? I needed to do that when using an SFP in an CCR1036 SFP+ cage.

Indeed it does work. Is this expected? How come they cannot auto-negotiate?

I don’t know why it doesn’t autonegotiate, but it’s in the docs that you need to fix the speed & duplex when using an optical SFP in an SFP+ cage, and autoneg won’t work. A DAC isn’t optical of course, but you are effectively trying to do the same thing.

Didn’t find it anywhere although I could not actually find much on the docs regarding SFP apart from the compatibility list table.
Would you mind pointing me to the section you are mentioning?

Thanks again

It’s here:

https://wiki.mikrotik.com/wiki/MikroTik_wired_interface_compatibility#SFP+_interface_compatibility_with_1G_optical_transceivers

Does take a bit of digging, and I have been bitten by it when using a 1000BASE-BX-U SFP in my CCR1036.