Intermittent packet loss may occur when bridging is configured on NSX

Products

• VMware NSX Networking
• VMware vSphere ESXi

Issue/Introduction

Symptoms:
Intermittent packet loss may occur when you've configured bridging (say for L2VPN network extension) when the following conditions are met:

• NIC driver with VMDQ loopback feature in Intel NIC is used(eg, Intel X710).
• MAC learning feature on vDS is enabled on NSX Edge Node that is performing bridging. 

Environment

VMware vSphere ESXi 8.0
VMware vSphere ESXi 7.0
VMware NSX-T Data Center
VMware NSX-T Data Center 4.x
VMware NSX-T Data Center 3.x

Cause

VMDQ loopback feature used by Intel NIC can cause connectivity issues when MAC learning is used on NSX Edge Node (with bridging). The broadcast packets reflected by VMDQ loopback feature on physical NIC can cause MACs learned from edge node to move to uplink and as a result some packets may get lost.

Resolution

Turn off VMDQ loopback feature in Intel NIC following the step below. 

1. Install a Intel esxcli plug-in tool by following the Intel esxcli plug-in for managing Intel(r) Ethernet Network Adapters (66772) .

2. Run the following command in SSH console.

   # esxcli intnet misc vmdqlb -e 0 -n vmnicX

Note: The above configuration to disable VMDQ loopback feature is not consistent across reboot. To make this setting persistent, please add the command to rc.local by following Modifying the rc.local or local.sh file in ESX/ESXi to execute commands while booting (2043564)