Packet Loss due to LLDP Agent Feature X710 / XL710 on Linux with i40e

[ok-stp]

We are operating a Dell PowerEdge R750 (2x Intel Xeon Silver 4309Y) with an Intel X710-T4L network card (firmware 23.0.8). The system runs Oracle Linux 8.10 with the 5.15.0-301.163.5.2.el8uek.x86_64 kernel. This server is used for monitoring VoIP/RTP data. It receives network traffic from various systems mirrored via a "Network Packet Broker" that aggregates multiple network TAPs. The Intel NIC operates in promiscuous mode, capturing and analyzing the data.

For several months, we have observed periodic packet loss in the analysis. Approximately every 10 to 20 seconds no network packets are received for 20-25ms, even though they are present. When we connect the link to an identical server running Windows Server 2022, we do not observe this packet loss.

The issue was raised with the software and OS providers, as well as the server manufacturer, but after months of investigation, no root cause was identified.

The problem has now been isolated. The cause is the LLDP agent, which is enabled by default on Intel X710 and XL710 NICs. By disabling the LLDP agent on the card via ethtool with:

ethtool --set-priv-flags em3 disable-fw-lldp on

we no longer experience packet loss (and the LLDP packets are now also passed through to the OS).

This suggests a potential issue with the driver or the operating system, as this problem does not occur on the Windows system, even though the same network card with the same firmware version is installed there, with the LLDP agent also enabled.

Same Problem exists with Rocky Linux 8.10 with Kernel 4.18.0-553.el8_10.x86_64.

Does anyone have any insights on whether this might be an issue with the i40e driver or a kernel issue?

Has anyone observed similar behavior?

Kind Regards

Oliver

[Tss0]

This feature has been a source of problems for me for many years.  It causes problems with lacp port channels, and I believe other issues. Since you are running on Dell, you can also disable on the card so no need to create a network dispatcher on your el8/el9 system.