Error "Routed network advertisement subnet <IP Address> and edge gateway service. external network's subnet <IP Address> should not overlap." while adding network in the BGP over the edge.

Products

• VMware Cloud Director

Issue/Introduction

• When attempting to add network in the BGP over the edge in the Tenant portal, the operation fails. with error
  • Error: [ #### ] Routed network advertisement subnet <IP Address> and edge gateway service. external network's subnet <IP Address> should not overlap.
• The error message in VCD may not directly indicate an issue with NSX route advertisement rules.
• 

Environment

VMware Cloud Director 10.x

Cause

A stale entry referencing the same IP from the error may be found configured on the Tier-1 Gateway in NSX-T causing conflict

Resolution

 

• Identify the Affected Tier-1 Gateway: Determine which Tier-1 Gateway in NSX-T is associated with the VCD Provider VDC or Organization VDC where the network addition is failing.
• Verify Route Advertisement Rules:
  • Log in to the NSX-T Manager.
  • Navigate to Networking > Connectivity.
  • Select the affected Tier-1 Gateway.
  • Go to the Route Advertisement tab.
  • Examine the configured Route Advertisement Rules.
  • Look for any unexpected or stale entries, specifically entries related to the network you are trying to add or potentially conflicting subnets.
• Delete the Stale Route Advertisement Rule:
  • If the problematic entry is found, delete it
• Attempt to Add the Network in VCD Again: After deleting the stale route advertisement rule in NSX-T, try adding the network in VMware Cloud Director. The operation should now be successful.