During my internship on the Internet Measurement Research team, I extended ThousandEyes' Event Detection pipeline to Android agents measuring over 4G/5G. Cellular networks hide the radio access network inside GTP tunnels and mask the real gateway infrastructure behind session-specific IP addresses, so the system could tell that cellular was involved but not where inside the network a failure occurred. The post covers what we built, what we found, and the RAN visibility and gateway mapping needed for end-to-end cellular event detection.

Mobile network geolocation errors are more than 10× worse than fixed broadband, with Africa and Asia seeing failure rates of 66–72% and 53–61% respectively, compared to under 20% in Europe. The problem is structural and provider-independent: geolocation prefixes covering mobile networks span vast geographic areas, and coarser address blocks are two to three times more prevalent in the Global South than in the Global North.