Is Internet RTT reliable for geolocation?

Short, short answer: nope, don’t bother. While this is probably obvious to any of you with network engineering experience, we thought we’d use RIPE Atlas to have a look into this question anyway.

In the context of an ongoing conversation about the explicit exposure of RTT information to devices on path in the IETF standard version of the QUIC protocol, we’ve briefly looked into how much of a threat Internet-observable per-path RTT is to geoprivacy of one of the endpoints. It turns out that the old network operations rule of thumb that a millisecond of RTT is 100km long adds a whole lot of uncertainty — a fact which also confounded some recent work on RTT-based anycast detection by Cicalese et al. Only in cases where one is very, very lucky — microseconds lucky — in the placement of the vantage points from which RTT measurements are taken can one use RTT measurements for elimination-based geolocation.

Our full white paper — which is also an experiment in “runnable papers” using Jupyter notebooks — is available on GitHub.

About Brian Trammell

Brian Trammell is an Internet measurement and architecture geek, a senior researcher at ETH Zürich's Networked Systems Group, and a member of the Internet Architecture Board.