Network BGP Diagnostics
Use this skill when a BGP session is down, flapping, established with missing routes, or advertising unexpected prefixes. The default workflow is read-only evidence collection; policy and reset actions belong in a reviewed change window.
When to Use
- BGP neighbors are stuck in Idle, Connect, Active, OpenSent, or OpenConfirm.
- A session is Established but expected prefixes are missing.
- A route-map, prefix-list, max-prefix limit, or AS path policy may be filtering routes.
- You need before/after evidence for a BGP change.
- You are reviewing automation that parses BGP summary output.
Read-Only Triage Flow
- Identify the exact neighbor, address family, VRF, and local/remote ASNs.
- Capture summary state and last reset reason.
- Prove reachability to the peer source address.
- Check route policy references before assuming transport failure.
- Compare advertised, received, and installed routes where the platform supports those commands.
show bgp summary
show bgp neighbors <peer>
show ip route <peer>
show tcp brief | include <peer>|:179
show logging | include BGP|<peer>
show running-config | section router bgp
show ip prefix-lis…
