CN

Switching Mellanox NICs Between IB and Ethernet Modes

Time: 2025-10-14
        Mellanox VPI network cards support dual operating modes (Infiniband/IB and Ethernet) and can be switched according to practical needs.
        The following demonstrates how to view and switch the operating mode of a Mellanox NIC using the MELLANOX MCX556A-ECAT as an example. This demonstration is performed on a CentOS 7.6 system.
1. Execute "mst start" to launch the MST tool. Use "mst status" to view the MST devices. The device name for the MELLANOX MCX556A-ECAT adapter in this demonstration is mt4119_pciconf0.
2. Run the command "mlxconfig -d /dev/mst/<device> query", replacing <device> with the adapter's device name. After executing the command, you can see that the MELLANOX MCX556A-ECAT network card is a VPI adapter card supporting both EDR IB and 100GbE Ethernet. Check the LINK_TYPE_P1 (P2) configuration under Configurations to confirm that both P1 and P2 ports are in IB mode.
3. Use the command "mlxconfig -d /dev/mst/<device> set LINK_TYPE_P1=1 LINK_TYPE_P2=1" to modify the NIC mode to either IB or Ethernet mode, where IB mode is 1 and Ethernet mode is 2. After executing the command, press y to confirm. Reboot the device to load the new configuration.
        Modifying to IB mode: mlxconfig -d /dev/mst/<device> set LINK_TYPE_P1=1 LINK_TYPE_P2=1

        Modifying to Ethernet mode: mlxconfig -d /dev/mst/<device> set LINK_TYPE_P1=2 LINK_TYPE_P2=2

4. After switching modes, verify LINK status, module identification, and DOM (Digital Optical Monitoring) using QSFP28-100G-SR4 optical modules on the MELLANOX MCX556A-ECAT NIC. Tests confirm that module info and DOM are readable in both modes, with LINK rates of EDR (in IB mode) and 100GbE (in Ethernet mode)."
Table 1 Optical Module Test in Both Modes
Mode
LINK Information
Identification and DOM Information
IB Mode
Ethernet Mode
        ModuleTek Limited is at your service !
        If you have any questions about the above content, you can contact us by Email : web@moduletek.com.
Back
PREVIOUS：Nothing
NEXT：How to Configure Interface Breakout and Aggregate on Ruijie RG-S6510 Series Switches