Partner Gateway running BGP may continue to advertise the SD-WAN Edge's subnet after the advertise flag is set to False.

Products

• VMWare SD-WAN

Issue/Introduction

A VMware SD-WAN Partner Gateway may continue to advertise a VMware SD-WAN Edge's LAN subnet after that subnet's advertise flag is set to False. This behavior may lead to routing issues due to the undesired routing advertisement. 

The behavior is seen with a customer using multiple Partner Gateways running BGP with Edges also using BGP, and after the BGP neighbor adjacency goes down at the Edge level.

 

Environment

VMware SD-WAN

Cause

The routes continue to be advertised because when the Edge breaks the BGP neighbor adjacency, one of the connected Partner Gateways maintains the stale route of the Edge LAN subnet.

Resolution

The fix for this issue is found on the following VMware Gateway Releases:

• On Release 4.3.1, the fix is included with the 4.3.1 Gateway Rollup #8: R431-20220510-GA which was released on May 17th, 2022, and all later Gateway builds in this release train.
• Upcoming Release 4.5.1 Gateway Rollup #1 (GA date TBD).
• All Release 5.0.0.0 GA builds and upcoming builds on this release train (for example, upcoming Release 5.0.1.0).

Workaround:

The only way to remediate the issue and clear the stale BGP routes is for a Partner or Operator to restart the Partner Gateway service in a suitable maintenance window. 

A customer who does not have direct access to the Partner Gateways can contact VMware SD-WAN Support to assist in restarting the Partner Gateway service.

Additional Information

Stale routes on a Partner Gateway negatively affect customer traffic destined to the affected BGP subnets and can lead to entire customer flows getting dropped because traffic is routed to non-existent routes.