ESXi host is reporting "Faulty TEP" alert on the NSX UI

Products

• VMware NSX

Issue/Introduction

- When workloads are moved to ESXi Transport Node the TEP (Tunnel Endpoint) status shows Tunnels towards Host to Host and Edges as down.
- TEP tunnel failures between ESXi host to hosts and Edge nodes.
- The host is only forming BFD session with VMK11 and not with VMK10.

Environment

VMware NSX

Cause

- We identified the connectivity issue is present only on one of the VMNIC and failing to form BFD session with host to host and edge nodes.

Resolution

- We referred this KB article and validated the Inter-vlan routing is good -- TEP tunnels are down between ESXi Transport Node and Edge Transport Node. (Alarm: Event type: Faulty TEP)

-  To resolve vmnic issue we manually flapped the problematic uplink vmnic# by running the below command.

• esxcli network nic down -n vmnic#  --> This puts the interface vmnic# down
• esxcli network nic up -n vmnic#   --> This gets the interface vmnic# up

If downing and upping the vmnic doesn't work:

• Remove the host from the cluster in vSphere 
• In the NSX UI, under other nodes, you will need that NSX is being removed from the host.
  • Wait until that is finished.
• In vSphere, move the host back to the cluster
• In NSX, you will see the host being reconfigured with NSX.