new talk “Digging in to Ground Truth in Network Measurements” at the TMA PhD School 2017

John Heidemann gave the talk “Digging in to Ground Truth in Network Measurements” at the TMA PhD School 2017 in Dublin, Ireland on June 19, 2017.  Slides are available at
From the abstract:

New network measurements are great–you can learn about the whole world! But new network measurements are horrible–are you sure you learn about the world, and not about bugs in your code or approach? New scientific approaches must be tested and ultimately calibrated against ground truth. Yet ground truth about the Internet can be quite difficult—often network operators themselves do not know all the details of their network. This talk will explore the role of ground truth in network measurement: getting it when you can, alternatives when it’s imperfect, and what we learn when none is available.


This talk builds on research over the last decade with many people, and the slides include some discussion from the TMA PhD school audience.

Travel to the TMA PhD school was supported by ACM, ISI, and the DHS Retro-Future Bridge and Outages project.

Update 2017-07-05: The TMA folks have posted video of this “Ground Truth” talk to YouTube if you want to relive the glory of a warm afternoon in Dublin.


new animation “Watching the Internet Sleep”

Does the Internet sleep? Yes, and we have the video!

We have recently put together a video showing 35 days of Internet address usage as observed from Trinocular, our outage detection system.

The Internet sleeps: address use in South America is low (blue) in the early morning, while India is high (red) in afternoon.
The Internet sleeps: address use in South America is low (blue) in the early morning, while India is high (red) in afternoon.

The Internet sleeps: address use in South America is low (blue) in the early morning, while India is high (red) in afternoon.  When we look at address usage over time, we see that some parts of the globe have daily swings of +/-10% to 20% in the number of active addresses. In China, India, eastern Europe and much of South America, the Internet sleeps.

Understanding when the Internet sleeps is important to understand how different country’s network policies affect use, it is part of outage detection, and it is a piece of improving our long-term goal of understanding exactly how big the Internet is.

See for the video, or read our technical paper “When the Internet Sleeps: Correlating Diurnal Networks With External Factors” by Quan, Heidemann, and Pradkin, to appear at ACM IMC, Nov. 2014.

Datasets (listed here) used in generating this video are available.

This work is partly supported by DHS S&T, Cyber Security division, agreement FA8750-12-2-0344 (under AFRL) and N66001-13-C-3001 (under SPAWAR).  The views contained
herein are those of the authors and do not necessarily represent those of DHS or the U.S. Government.  This work was classified by USC’s IRB as non-human subjects research (IIR00001648).


new video “A Retrospective on an Australian Routing Event”

On 2012-02-23, hardware problems in an Australian ISP (Dodo) router caused it to announce many global routes to their ISP (Telstra), and from there to others.

The result: for 45 minutes, millions of Australians lost international Internet connectivity.

While this problem was detected and corrected in less than an hour, this kind of problem can reoccur.

In this video we show the Internet address space (IPv4) from Sydney, Australia.   Colors show estimated physical location (blue: North America, Red: Europe, Green: Asia).   Addresses map to a Hilbert Curve, and nearby addresses form squares.  White boxes show routing changes, with bursts after 02:40 UTC.

In the visualization we see there are many, many routing changes for much of Internet (the many white boxes)–evidence of routing instability in Sydney.

A copy of this video is also available at Vimeo (some system may have problems viewing the above embedded video, but Vimeo is a good alternative).

This video was made by Kaustubh Gadkari, John Heidemann, Cathie Olschanowsky, Christos Papadopoulos, Yuri Pradkin, and Lawrence Weikum at University of Southern California/Information Sciences Institute (USC/ISI) and Colorado State University/Computer Science (CSU).

This video uses software developed at USC/ISI and CSU:  Retro-future Time Travel, the LANDER IPv4 Web Address Browser, and BGPMon, the BGP logging and monitor.  Data from this video is available from BGPMon and PREDICT (or the authors).

This work was supported by DHS S&T (BGPMon, contract N66001-08-C-2028; LANDER, contract D08PC75599, admin. by SPAWAR; LACREND, contract FA8750-12-2-0344, admin. by AFRL; Retro-future, contract N66001-13-C-3001, admin. by SPAWAR), and NSF/CISE (BGPMon, grant CNS-1305404).  Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of funding and administrative agencies.