Troubleshooting WAN link Dead events or WAN link flaps

Products

• VMware VeloCloud SD-WAN

Issue/Introduction

Edge frequently report WAN link DEAD alert on the VCO events page.

 

 

Environment

All VMWare Velocloud SD-WAN versions

Cause

Common scenarios when WAN link are flapped, If there is no active tunnel on a WAN link, the link will be marked as DEAD, and the Edge will send an alert to the VCO.

Please check below details to understand if its ISP issue or not.

• Check if the physical Link is up or down from Remote diagnostic page.
• If the physical link is up, please verify if the next hop arp is available for WAN link in arp cache.
• If arp is available , verify with capture if the we do send MP_Init packet and response is seen.
• Check for unstable,packet loss events from diag bundle edged logs to verify if the issue is intermittent.

Resolution

To isolate the issue, do packet capture  from the VCO. Request Packet Capture Bundle

One-way traffic during the issue indicates that the Edge is sending traffic, but it is being dropped somewhere within the transit network.

Raise case to support team to check on Edge side if the Edge was not sending traffic during issue state.