Network & Infrastructure / BGP Policy & Internet Edge
Conditional default origination and upstream service failure
A branch receives a default route from its hub even after the hub loses useful upstream connectivity. The BGP session between branch and hub remains healthy throughout the outage.
Environment and inputs: BGP speakers and route reflectors; policy syntax, RPKI integration and address-family behavior depend on the implementation. Diagnostic/design example; not tested on production equipment.
Collect the evidence
Inspect default-origination policy, dependency routes, tracked probes and route ownership. Check whether the tracked target can accidentally resolve through the very default being advertised.
Explain the result
A configured default can express administrative intent rather than tested Internet reachability. Recursive tracking can keep the advertisement alive through an unrelated or looping fallback path.
Plan the fix
Define an explicit availability condition using independent routing and service evidence. Ensure the dependency cannot be satisfied by the generated route itself or by an unintended backup path.
Check the result and rollback
Remove each upstream in turn and verify branch selection and restoration timing. Revert if the condition flaps, suppresses a valid backup or advertises availability before useful forwarding has recovered.