Mobile and Cellular Networks from the Edge

What the network looks like from a phone, a plane, and a roaming SIM.

Last updated on Aug 14, 2026 Research

Project Overview

For most people on Earth, the Internet is reached over a cellular network. Yet cellular infrastructure is among the hardest of all networks to observe: the interesting behaviour happens inside operator networks that publish little, use private addressing, and terminate traffic at gateways whose location bears no simple relation to the user’s.

The consistent move in this thread is to measure from the client, where a handset can see what an outside prober cannot, and to keep asking a question that outsiders usually assume away: for a mobile user, where is the network actually, and what does that cost?

Cellular Networks in the Internet

Cell Spotting mapped where cellular traffic enters the Internet, showing that the gateways serving mobile users are far more concentrated and far less local than the geography of their users implies. Behind the Curtain followed the consequence into content delivery: if a CDN sees a query arriving from a distant gateway, the replica it picks is wrong for the user holding the phone — the same problem our DNS work had found on fixed lines, sharper in cellular.

Anycast on the Move asked what happens to anycast routing when the client itself is moving, and Where Things Roam turned to cellular IoT and M2M connectivity, a population of devices that roams permanently by design.

Aggregators and Roaming

Roaming is no longer a bilateral arrangement between two operators. A layer of global aggregators now sits between the SIM and the networks that serve it, which changes the performance a device gets and makes the path it takes hard for anyone to predict. Our MobiSys paper laid out a taxonomy of these aggregators and measured their roaming performance and optimization, and the later TNSM article extends the comparison.

The Mobile Web

Mobile web performance has been shaped as much by intermediaries as by protocols. AMP up your Mobile Web Experience characterized what Google’s Accelerated Mobile Pages actually delivers, separating the gains attributable to the format from those attributable to serving from Google’s cache. Reining in Mobile Web Performance looked at what document and permission policies can recover, and Mobile AD(D) examined app session times, which determine what an ad — or any load — is worth paying for.

Connectivity in Motion

In-flight Internet is a useful extreme case: a satellite path, a shared cell with a hundred passengers, and a network stack designed for none of it. Mile High WiFi was a first look at in-flight connectivity in the wild, and When IPs Fly made the case for rethinking airline communication rather than treating the aircraft as an ordinary subscriber.

Papers

Cellular networks in the Internet

Aggregators and roaming

The mobile web

Connectivity in motion

Coverage

  • In-flight WiFi — Northwestern McCormick News, ChicagoInno, and the Chicago Tribune (2016)
  • The in-flight browsing extension — Network World, New Atlas, ScienceDaily, CACM News, Indian Express, and Travel+Leisure (2017)
  • Phone usage — Northwestern McCormick News and ACM TechNews (2016)

People

Lead & PI

Students

Collaborators

  • Andra Lutu (Telefónica Research)
  • Sergi Alcalá-Marín, Marcelo Bagnulo (Universidad Carlos III de Madrid)
  • Özgü Alay (University of Oslo)
  • Moritz Steiner (Akamai)
  • Vishnu Navda, Ranjita Bhagwan, Saikat Guha (Microsoft Research India)
Mobile Networks Cellular Web Performance Internet Measurement
Authors: John P. Rula , Byungjin Jun , Sergi Alcalá-Marín , Fabián E. Bustamante