Network-level path churn is critical for censor localization: 25%, 30%, 38%, and 67% of ICLab source-destination pairs observe distinct AS-level path changes over periods of one day, week, month, and year respectively. Without path churn, nearly 90% of constructed CNFs return five or more solutions (ambiguous), compared to less than 2% when multiple distinct paths are included.
From 2017-cho-churn — A Churn for the Better: Localizing Censorship using Network-level Path Churn and Network Tomography
· §4
· 2017
· Emerging Networking Experiments and Technologies
Implications
Monitor AS-level path churn to bridge and proxy servers as an early warning signal — sudden path stabilization routing through a known-censoring AS may indicate deliberate route manipulation targeting the circumvention infrastructure.
Path diversity between clients and proxies provides both reliability and enables tomographic censor localization; designs that deliberately vary routing paths improve the accuracy of any downstream measurement-based censor map.