Baltimore Data Day is an annual conference bringing together “community leaders, nonprofit organizations, government and civic-minded technologists to explore trends in community-based data and learn how other groups are using data to support and advance constructive change.” This year the 11th annual event expanded to become Baltimore Data Week, celebrating the 20th anniversary of the conference’s host organization, the Baltimore Neighborhood Indicators Alliance (BNIA). As a Baltimorean myself, I was honored to be invited to give a talk about the M-Lab platform and our open data, on the conference’s “Digital Inclusion Day.”

Evolution of NDT

NDT measures “bulk transport capacity”: the maximum date rate that TCP can reliably deliver data using the unreliable IP protocol over an end-to-end Internet path. TCP’s goal is to send data at exactly the optimal rate for the network, containing just the right mix of new data and retransmissions such that the receiver gets exactly one copy of everything. Since its creation, the TCP protocol has consistently made improvements to the way it accomplishes this task, consequently, NDT has also incrementally changed to reflect these improvements. The most recent improvements, including support for TCP BBR, are available in ndt7. On July 24th, we announced the start of migration of NDT clients to the latest protocol version. As of today, approximately 50% of clients are using ndt7. As the ndt7 measurements become the majority of the NDT dataset, the M-Lab team is considering what we do and do not know about whether and how changes to the NDT protocol have affected M-Lab’s longitudinal NDT dataset over time.

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