The Default Route Is a Fact, Not a UI Guess

A topology view should consume routing state rather than infer a gateway from labels or layout.

I keep this as a field note because the failure mode is easy to misclassify: presentation logic invents routing semantics. The useful move is to identify the boundary first, then change only the layer that owns it.

What I model

The system is easier to debug when intent, observation and transport are not collapsed into one state. For this case, my rule is simple: Routing facts should enter through telemetry, not drawing heuristics.

Implementation pattern

Carry next hop, interface and route identity from the kernel or collector into the normalized topology model.

I prefer a small explicit contract over a clever implicit one. That gives logs, tests and dashboards something concrete to verify and keeps unrelated layers from compensating for each other.

What I verify

• next hop is observed
• overlay routes are separate
• moving a node cannot change semantics

Failure handling

When one of those checks fails, I preserve the failing evidence before restarting or changing configuration. The first broken contract determines the next investigation. That keeps troubleshooting causal instead of turning it into a sequence of guesses.

What I keep

Routing facts should enter through telemetry, not drawing heuristics. The specific tools can change, but that ownership boundary remains useful across firmware, networks and infrastructure.