Can't get Mellanox ConnectX-4 CX455A to work at 100Gbps on CRS504-4XQ-IN

RouterOS General
1

Hi everybody!

Issue:
As per subject I can’t get the 100Gbps speed to work using a proper 100Gbps card on the CRS504.

Scenario:
CRS504-4XQ-IN with default script (all interfaces bridged), running RoS 7.9, using XQ+DA0001 DAC cables to hook up the servers.

Got a working link by disabling Auto Negotiation on the qsfp28-x-1interfaces: works fine at 40Gbps, can’t get it to 100Gbps on ConnectX-4 (looses link but ethtool still finds out that is a DAC cable), details:

  • Mellanox ConnectX-3 CX314A 10/40Gbps QSFP+ → Working by setting qsfp28-x-1 speed to 40Gbps full duplex
  • Mellanox ConnectX-4 CX455A 40/100Gbps QSFP28 → Working by setting qsfp28-x-1 speed to 40Gbps full duplex, fails to get link when set to 100Gbps.

any suggestions on what to look for? SFP FEC Mode? Other?

2

Hello,
its over a year, but I ran in the same issue and got it running by setting the fec-mode to fec91 on the interfaces.

Kind regards,
Daniel

3

can you test it connection iperf3? at connectx3 adn 5 i cant get 40G only 10G