BFD Session Troubleshooting

In order for a Bidirectional Forwarding Detection (BFD) session to successfully operate, it requires connectivity between the neighbors. However, BFD sessions may fail to establish despite having connectivity between neighbors. Common reasons for BFD session failures include:

1. Configuration mismatch: Ensure BFD is configured on both ends of the link and verify that the BFD intervals and timers such as bfd interval and bfd min-receive values match on both devices.

2. Incorrect interface configuration: Confirm that BFD is configured on the correct interface.

3. Routing protocol integration issues: If BFD is tied to a routing protocol (e.g., OSPF), verify that:

   • The routing protocol is operational
   • BFD failure detection is correctly configured for the routing protocol
   • The routing protocol has successfully established an adjacency

To further troubleshoot BFD issues, use the following debug commands:

• debug bfd events
• debug bfd packets
• debug ip bfd

These commands can provide detailed information about BFD operations and help identify the root cause of session failures.

Links

https://networklessons.com/cisco/ccie-routing-switching/bidirectional-forwarding-detection-bfd