QM9700 break out to 2x200g

Infrastructure & Networking Switches and Gateways InfiniBand/VPI Switch Systems
1

Have a QM9700 running MLNX-OS 3.11.1004. Split config is enabled, and we have the MMA4Z00-NS breaking out to 2x400G CX7 400G cards with no issue. We now need to add 200G connections of QM8700s with MMA1T00-HS connecting to the MMA4Z00-NS in the 9700 to the mix. It’s temporary until we replace the 8700s. I know the optics can do it functionally, as we do it in Juniper systems, but not having any luck here. How do i configure the port on the 9700 to support this?

2

Hello,

You need HDR on both ends. See below:
https://docs.nvidia.com/networking/display/nvidiaquantum2firmwarereleasenotesv3120143062/firmware+compatible+products#src-3593241475_FirmwareCompatibleProducts-Switch-to-SwitchConnectivity

3

Then how would the MCP7Y40-N002 work? It’s NDR on the 800G end, HDR on the 200G in a CX-7 200G card.

4

Yeah, unfortunately, you can’t mix 400G and 200G on the same MMA4Z00-NS port on a QM9700. I ran into this before — Spectrum-4 MLNX-OS only supports the breakout modes the module defines, and it requires symmetric speeds per breakout group.

So your 2×400G breakout stays 400G on both sides — there’s no config trick to make one lane 200G. Works on Juniper because they allow more flexible lane mapping, but not here.

Practical options:

  • Use a native 200G port on the 9700.
  • Or run dedicated 200G optics from 9700 to the QM8700s.
  • Otherwise, keep everything at 400G until the 8700s are replaced.