I’m trying to setup a new network The core of the Network is a Huawei S6730-H24X6C switch. I’m now trying to connect a Server with a QNAP LAN-40G2SF-MLX card, a rebranded Mellanox ConnectX-3 Pro, to the switch. But neither the switch nor the server sets the link to UP.
When I connect both ends of the DAC to the network card both Interfaces change to up. The same happens, if I connect both ends to the switch.
If I connect the server and the switch nothing happens. I can see the transciever info of the DAC on both ends, but the connection won’t start.
I have seen, that the switch sets the link speed to 100Gbps, but the network card only supports 40Gbps. In documentation of the switch is stated, that it supports 40Gbps. i can’t set the link speed on the switch, nor can I enable auto-negotiation on the QSFP ports.
I have tested the card in two different systems. One running Ubuntu Server 20.04 and one running TrueNAS Scale 22.04.
Has somebody had a similar experience and can help me solve this problem?
Used Parts:
- QSFP+ Card QNAP rebranded ConnectX-3 Pro
- Huawei S6730-H24X6C switch
- Netgear DAC SFP28 ACC761-10000S
What do you mean here, what commands did you try? I’ve never used Huawei switches, but the below sounds like it will do what you need.
It sounds like you need the “undo assign port-speed 100GE” command to set the speed. (I’ve seen stranger configurations). After that you can use the “display device port-speed configuration” command to verify the configuration applied successfully.
Also maybe try a DAC cable that’s designed to support QSFP+ specifically. SFP/QSFP is technically forwards/backwards compatible, but the DAC/SFP may be coded for one speed only.
1 Like
Thanks for your Answer.
I had seen your link. But i can’t use this command on the 100GE Ports. I get the following error: unrecognized command found. The same command can be used on the 10GE ports of the same switch.
In regards of the DAC cable. The only one cable i have left, wont be recognized by either the switch or the network card. So I can’t test this at the moment.
But since the link on the network card goes up, when I connect both ends of the DAC to the network card, I think it is coded for 40Gbps speeds.
I had some time to test different things and to contact the HUAWEI support.
If you want to change the port speed of the QSFP28 from 100GB to 40GB, you have to run the command “undo assign port-type 100ge all” in the system-view. This will change the port speed of all QSFP28 Ports, after you rebooted the switch.
As soon as the port speed is changed, the name of the ports change from 100GE to 40GE. The QSFP28 cables, which was accepted in the 100GE modus, wasn’t be recognized. I have the same cable running between two QSFP+ (40GB) users without a problem. This excludes the cable coding as problem.
A QSFP+ cable was accepted without problem in the 40GE modus, which was ignored in the 100GE modus. This was an excepted behavior.