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BGP Troubleshooting Playbook
A diagnostic sequence that avoids random troubleshooting.
When BGP does not behave as expected, separate transport, session, reception, selection and advertisement. This sequence helps isolate the failing layer quickly.
- 01IP transport: reachability, source, TTL, ACL and return path
- 02Session: neighbor state, ASN, timers, authentication and capabilities
- 03Reception: prefix received or filtered before the RIB?
- 04Validation: resolvable next hop and admissible route?
- 05Selection: BGP attributes and competition with other paths
- 06Installation: route present in RIB/FIB?
- 07Advertisement: export policy, communities and redistribution conditions
- 08Dataplane: actual forwarding, ECMP, asymmetry and MTU
- 09Change control: compare with pre-incident baseline
- 10Evidence: capture commands and timestamps before modifying state