Tunnels between NSX Edge and ESXi Transport nodes showing as Down

Products

• VMware NSX

Issue/Introduction

• Tunnels between NSX Edge and ESXi transport nodes displays as Down even when there are no network connectivity issues.
• When placing packet capture on the ESXi host where the Edge vm resides, the INIT BFD packet will be seen on associated ESXi vmnic however not on the edge switchport.
• Tracing the packet using below capture point on the ESXi host 

  pktcap-uw --uplink <vmnic_number> --scrip <source_ip> --dstip <destination_ip> --trace

  "VXLAN Module Drop" reason will be seen
  
  
• 

Environment

VMware NSX-T Data Center 3.x

VMware NSX 4.x

Cause

This issue occurs because the Edge VM TEP interface is connected to a vDS portgroup on a host switch which is used/prepared by NSX.

Configuration issue on NSX-T Edge TEP networking options

 

Resolution

To resolve this issue, create a logical segment on the VDS and assign the Edge VM TEP interface.

For more information, refer  KB 317168 - NSX-T Edge TEP networking options.

Additional Information

Also Refer Tunnels between NSX-T Edge and ESXi nodes displays as Down even when there are no connectivity issues