BGP Neighbor down has been observed on XXXX alarm seen in VCF Operations/VROPs while no Alarms are observed in NSX.

Products

• VMware NSX
• VCF Operations

Issue/Introduction

• BGP down alarms are observed in VROPs but no issues or BGP errors can be seen in VMware NSX.
• The BGP IPs referenced belong in the 169.254.0.X Range.
• Inter-SR BGP is enabled within the NSX T0 configuration.
• No alarms are seen in NSX GUI for BGP.
• When checking NSX for open alarms via API the same alarms can be seen in an open state when checking with the below NSX APIs.
  • GET /api/v1/alarms?status=OPEN
  • GET /api/v1/alarms
• If the open alarm for the Inter-SR BGP is set to resolve via API, it will re-trigger the alarm with a new alarm ID immediately.
• Alarm similar to the below are observed in VCF Operations / VROPs:
  
  • BGP Neighbor down has been observed on <Collector ID>
  • In Router 5151XXXX-XXXX-XXXX-XXXX-XXXXXXXX46bf, BGP neighbor 470fXXXX-XXXX-XXXX-XXXX-XXXXXXXXf0ba (169.254.0.X) is down."

Environment

VMware NSX

VMware NSX-T Data Center

VCF Operations (Formerly VMware vRealize Operations)

Cause

When BGP goes to a fully down or disabled state, alarms are generated for all BGP links, including inter-SR BGP, regardless of its state. When BGP is restored, external alarms will be cleared due to state change, but if inter-SR BGP did not change state, the alarms will not clear.  

Inter-SR BGP alarms do not appear in the NSX alarm UI.

Resolution

As Inter-SR BGP links do not reflect live states after this alarm is triggered a full toggle of inter-sr BGP must be performed to reset the state and clear the alarm.

Follow the steps below to resolve the false alarms on the Inter-SR:

1. Disable the Inter-SR iBGP option in the UI or by using the API:
   • Navigate to: Networking -> Tier-0 Gateways -> T0 Edit -> BGP
   • Disable 'Inter SR iBGP'
     
     
2. Enable the Inter-SR iBGP option in the UI or by using the API:
   • Navigate to: Networking -> Tier-0 Gateways -> T0 Edit -> BGP
   • Enable 'Inter SR iBGP'
     
     
     

Note: This workaround of toggling Inter-SR sessions may disrupt any traffic via Inter-SR.

 

Additional Information

Similar KBs

NSX-T Manager alarms indicating Inter-SR BGP session down

NSX Precheck shows open alarm for BGP, but no BGP alarms are showing in NSX UI