Known Issues

Linux Kernel Upstream Release Notes v6.5

The following table provides a list of known bugs and limitations in regards to this release of WinOF-2. For a list of old Know Issues, please see the relevant Release Notes version.

Internal Ref.



Description: In case the user configs TCP to priority 0 with no VlanID, the packets will be sent without a VLAN header since the miniport cannot distinguish between priority 0 with VlanId 0 and no Vlan tag.

Workaround: N/A

Keywords: TCP QOS


Description: When using striding RQ with a WQE that is too small, the initialization process will fail, and a Yellow Bang will appear.

Workaround: Increase the WQE size

Keywords: striding rq


Description: NumaNodeID NDI values are defined as enum instead of min/max as defined in MSDN.

Workaround: Install the latest WinOF2 package

Keywords: NumdNodeID, MSDN


Description: The default value of "NumRSSQueues" is 8 instead of 16.

Workaround: Install latest driver package.

Keywords: NumRSSQueues


Description: Wrong rate limitation (120 Gbps) when using 200GbE adapter cards with port_type of IPoIB.

Workaround: install latest driver package

Keywords: Performance


Description: The default value of MaxRssProcessorsis 8 instead of 16.

Workaround: Install latest driver package.

Keywords: MaxRssProcessors


Description: The maximal value of VlanID is 4095 and not 4094

Workaround: 4095 is reserved and should not be used

Keywords: VlanID


Description: In some cases, the adapter's name can be trimmed in the Event log messages when the message size was larger than the Event log message limit size (240 characters).

Workaround: N/A

Keywords: Event log message size


Description: Due to memory allocation issue, an issue with the MST dump might occur.

Workaround: N/A

Keywords: MST dump memory allocation


Description: As PCIe Write Relaxed Ordering is enabled by default, some older Intel processors might observe up to 5% packet loss in high packet rate and small packets. (

Workaround: Disable the Relaxed Ordering Write option by setting the RelaxedOrderingWrite registry key to 0 and restart the adapter.

Keywords: PCIe Write Relaxed Ordering


Description: Mellanox Device Diagnostics counters do not function properly when using a NIC with two adapters in the following flow:
1. Enable adapter 12. Enable adapter 23. Query Mellanox Device Diagnostics counters continuously4. Disable adapter 1
The counters for adapter #2 will stop working and the following error message will be shown in the event log for command failure: : FW command fails. op 0x821, status 0x4, errno -5, syndrome 0x993ca6.

Workaround: Restart adapter #2 or enable adapter #1

Keywords: Mellanox Device Diagnostics counters


Description: When running RoCE traffic with a different RoceFrameSize configuration, and the fabric (jumbo packet size) is large enough, the MTU will be taken from the initiator even when it supports larger size than the server.

Workaround: N/A

Keywords: RoCE, MTU


Description: The driver ignores the value set by the "*NumVfs" key. The maximal number of VFs is the maximal number of VFs supported by the hardware.

Workaround: N/A

Keywords: SR-IOV NUMVFs


Description: Issues with the OS' "SR-IOV PF/VF Backchannel Communication" mechanism in Windows Server 2019 Hyper-V, effect VF-Counters functionality as well.

Workaround: N/A

Keywords: Mellanox WinOF-2 VF Port Traffic, VF-Counters


Description: On WIndows Server 2019, the physical media type of the IPoIB NIC will be 802.3 and not InfiniBand.

Workaround: Use the mlx5cmd tool ("mlx5cmd -stat") which is part of the driver package to display the lin_layer type.

Keywords: Windows Server 2019, IPoIB NdisPhysicalMedium


Description: When working with SR-IOV in Windows Server 2019, the vNIC that is working in SR-IOV mode status will be displayed as "Degraded (SR-IOV not operational)" although the SR-IOV VF is fully operational. The message can be safely ignored.

Workaround: N/A

Keywords: SR-IOV IB, Windows Server 2019


Description: iSCSI boot over IPoIB is currently not supported.

Workaround: N/A

Keywords: iSCSI Boot, IPoIB


Description: On servers with large number of VMs, (typically more than 40), after restarting the NIC on the host, VMs' IPv6 global address is not retrieved back from the DHCP.

Workaround: Restart the NIC inside the VM.

Keywords: VMQ, SR-IOV


Description: Due to an OID timeout, the miniport reset is executed.

Workaround: Increase the timeout value in such way that 2 * CheckForHangTOInSeconds > Max OID time.
For further information, refer to section General Registry Keys in the User Manual.

Keywords: Resiliency


Description: When PXE boot is using Flexboot, the IPoIB interface is not receiving the reserved address from the DHCP using GUID reservation.

Workaround: To obtain the reserved address, use a 6-byte MAC address instead of the 8-byte client ID.

Keywords: PXE boot, IPoIB, Flexboot, DHCP


Description: The driver must be restarted in order to switch from RSS to NonRSS mode. Therefore, if a PowerShell command is used on a specific VM to an enabled/disabled VMMQ without restarting the driver, the RSS counters will keep increasing in Perfmon.

Workaround: Restart the driver to switch to NonRSS mode.

Keywords: RSS, NonRSS, VMMQ


Description: In RoCE, the maximum MTU of WinOF-2 (4k) is greater than the maximum MTU of WinOF (2k). As a result, when working with MTU greater than 2k, WinOF and WinOF-2 cannot operate together.

Workaround: N/A

Keywords: RoCE, MTU


Description: In IPoIB SR-IOV setup, in the Hyper-V Manager, the address appears as "SR-IOV enabled" instead of "SR-IOV active". This does not influence any activity or functionality.

Workaround: N/A

Keywords: IPoIB SR-IOV setup, Hyper-V


Description: In the "Network Connections" panel of Virtual Function (VF) in IPoIB SR-IOV setup, the Microsoft adapter may appear in addition to the Mellanox adapter. This does not influence any activity or functionality.

Workaround: N/A

Keywords: Network Connections, VF, IPoIB SR-IOV

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