Hello, I plan to split an NVIDIA BlueField-3 (model: 900-9D3B4-00PN-EA0, single-port QSFP112 400GbE) into two 200GbE links using a QSFP112→2×QSFP56 breakout cable, connect them to two QSFP56 200GbE ports on a Mellanox SN3700, and enable LACP on the switch to aggregate the two ports, with the goal of achieving the theoretical 400GbE rate. I would like the official/community to confirm whether this topology is valid. If it is, I would like to know the minimum firmware/DOCA/BSP versions and configuration requirements on the BlueField-3 side, the recommended practices for configuring LAG (LACP active) on the SN3700 (Onyx), and whether there are any official documents or example configuration snippets/lists that I can reference. I would appreciate your guidance. Thank you.
- Here is the ref list of Bluefield-3 validated and supported cables and modules
https://docs.nvidia.com/doca/sdk/bluefield-3+validated+and+supported+cables+and+modules/index.html
- When using splitter cables the end cable either x2 or x4 is only on the host(s) side, the other side of the cable (single end) is only for the switch side.
From your description, you have it backwards.
What you describe is not a valid/supported configuration.
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You have a single port, why not using a 400Gbs cable for the full rate?
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Beside the non-valid configuration posted, I don’t see the use case of deploying LACP from a single port which is already @400Gbs.
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As a best practice we recommend installing the latest BFB image which embed the FW.
this is really sad, because we also have a similar use case. QSFP28 (100G) on the Bluefield-3 side and the “split-end” 2xQSFP28 on 2 different Switches (each 50G).
This seems not be working and of course NVIDIA did NOT MENTION this on their product pages.
Please @spruitt make sure that this is HIGHLIGHTED an a) your Validated Cables and b) on your Bluefield-3 specs EVERYWHERE.