Four ways a route disappears

Abstract

Four quiet failures of hub-and-spoke routing, each drawn the safe way and the trap way: a summary partly outside its filter, a static route shadowed by a learned one, peering that is not transitive, and a call across the hub that is answered with not found.

The routes that fail silently are the ones a design has to test for, because nothing will report them.

Its figure in the paper: § III.A →

The inputs

The situation

How it is drawn

The outcome

dropped silently

The summary spans blocks 10 to 40; the filter includes 10 to 30. Only part of it is inside, so the whole summary is dropped, and no error says so.

The controls that apply

Filters include whole summaries, or the summary is split to fit.
A test asserts each expected route arrives.

The record · 0 receipts

verified · 0

Nothing has been decided yet.

Try to break it

A claim stands because the attacks on it were attempted and refused. Each one runs against the instrument's own rules. 0 of 2 attempted · 0 refused

Trust the filter to keep a summary
Draw the summary wider than the include range and expect it to arrive.
Reach a third spoke through a second
Rely on two peerings to make one path.

Setting up the instrument…

Declared limits

Addresses are abstract numbered blocks, never real ranges.
Generic and illustrative throughout: the behaviour is shown, the internals of the systems it is drawn from are not.

Instruments beside it in § III.A

Every attack in the laboratory, on one page: try to break all of it →

Everything you did in the laboratory, in one chain you can rewind: the notebook →