Are there any secrets to using a qsfp -> sfp adapter? Setting link speed is not enough.

I’m trying to use a qsfp → sfp adapter with a SN2100 switch and I can’t get the link to come up. Are there any secrets to this? According to the documentation I need to set the link speed on the switch, but that isn’t enough, the link doesn’t come up. I’m using the adapter to convert from 25G at the device, to in the 100G switch.

Hello Simon,

Thank you for posting your inquiry on the NVIDIA Networking Community.

For converting from 100GbE to 25GbE, we only support the following QSA adapter in the SN2100 switch → MAM1Q00A-QSA28 →

We also recommend to upgrade the switch code to the latest version 3.9.2302.

If you still experiencing issues with the us of the Mellanox QSA adapter, we recommend to open a NVIDIA Networking support ticket (valid support contract required) so we can better assist you. To open a ticket, please send an email to

Thank you and regards,

~NVIDIA Networking Technical Support