Cluster members must not advertise to overlay the BGP routes with different AS Length

Products

• VMware VeloCloud SD-WAN Edge Appliance
• VMware VeloCloud SD-WAN

Issue/Introduction

All members of the cluster should have the same AS Length for the routes learned from the LAN. If the as length is different for any member of the cluster this can cause a routing issue.

Ideally we should not configure BGP filters to add different AS Prepend on each member of the Cluster. 

Environment

VMware SD-WAN by VeloCloud
VMware SD-WAN

Cause

When routes have different AS path lengths, SD-WAN will prefer the route with the shortest length rather than based on cluster member assignment.

Resolution

To prevent this from happening the recommendation is that all edges within the cluster have identical BGP configurations.