ConnectX6-DX 100G configuration required to be used as 4x25G

Infrastructure & Networking Adapters and Cables Ethernet Adapter Cards
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1

Hello community!
Hopefully someone here can help me with my question. I am basically looking for the configuration required on the ConnectX6-DX NIC to change it from 1x100G Ethernet to 4x25G Ethernet. I have found information on how to do this on the switch here, but I was wondering how to do this on the server side NIC instead (if possible!).

Thanks!

2

NIC port cannot be physically splitted.
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3

Thanks for your reply @dwaxman . Is there another NIC model from Nvidia/Mellanox that supports this feature? I know for a fact that Emulex/Broadcom have this kind of feature (break-out cable support) in some of their NICs because I used in the past.

4

Can you confirm @dwaxman, that the ConnectX cards do not support (eg, 4x25G) breakout cables?

5

Hi,

The NICs do not support splitting physical lanes (unlike switch ports)

I’m not familiar with a usage scenario that requires a NIC port physically splitted to 4 ports.

6

Just for the thread completeness…
As advised in this thread, Mellanox NICs do not support it so we ended up using an Intel one that supports this:
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Source: Ethernet Port Configuration Tool Infographic – Intel

7

We do also actively use such a mode with the Intel cards.
It would have been nice to have another option in case there is a shortage, but ConnectX is ruled out then.

8

Which is sorry ;(

So, MY case is where I’m using SuperMicro “SuperServers”/TwinPro 2U 4node servers as my cabinet router/“switches” and with 2x 100G QSFP28 -breakout to 4x25G SFP28 ports, I suddenly have 2x 2x 4xSFP28 (16xSFP28) possible ports per node to connect the mesh routing to the rest of the servers in the cabinet (typically a half rack, and yes, space/budget constraints)

But that is my usage scenario where the switches would be superfluous extra hops not wanted/needed in the meshed cluster setups