So I’m honestly looking to see if this was a simple oversight in the software for the M7308R-4X switch.
I can:
-Break out a QSFP28 100gbe connection to 4x25gbe (4x sfp28) no problem.
-Break out a QSFP+ 40gbe connection to 4x10gbe (4x sfp+) no problem.
-Set a broken-out 100gbe→4x25gbe connection to a 4x LACP LAG trunk to attach to say an upstream 25gbe switch using 4x sfp28s. Set up the LACP on both ends, works great.
But what I CANNOT do is:
-Set a broken-out 40gbe→4x10gbe connection to a 4x LACP LAG trunk.
It immediately sets the LACP group to attempted 4x25gbe, even if it’s a 40gbe/4x10gbe link. (And the result is, the entire link/breakout just shuts down.)
This really seems like a minor inconsistency that very well may be a bug? Basically I need to connect two devices upstream, one being a 4x25gbe LACP via 100gbe QSFP28, and another device, 4x10gbe LACP via 40gbe QSFP+ . The first works, the second just fails.
Could QNAP look into this, or is this something I’m missing in configuration? (I set the breakout ports to all 10gbe before I create the LACP group, but it doesn’t matter. In the breakout configuration page it still claims its 4x25gbe even though it isn’t.)
Hi @Michi ,
Thank you for your detailed description and for sharing the test scenarios you have gone through. We appreciate the time you spent verifying the different breakout and LACP combinations.
Based on our review, this behavior is related to the LAG interface speed setting. When creating the LACP group for a QSFP+ 40GbE breakout (4 × 10GbE), the LAG speed is currently defaulted to 25GbE, which leads to the link being brought down.
To resolve this issue, please go to the Port Management page and manually change the LAG speed from 25G to 10G before applying or finalizing the LACP settings (not port speed). Once the LAG speed is set to 10GbE, the 4 × 10GbE breakout ports should be able to form the LACP group correctly and operate as expected.
If the issue persists after applying this setting, please let us know and we will be happy to assist with further investigation. Thank you again for your feedback, which is very helpful for improving our products.
Could you share the model of the 40G QSFP to 4 10G breakout cable please? I tried a 40G QSFP → MDO that split to 4x LC duplex. This did not yield any link on the switch. I have the latest firmware loaded on to the switch (4.3.0 build 20250904) and the switch it configured in the breakout with each sub interface set to 10G. No luck. What I really need is a 40G QSFP → 4x 10G LC duplex, not finding that directly so I tried QSFP → MDO → 4x LC duplex. Note that I am able to break out 100G to 4x 25G on the switch, so the configuration is understood.