Observing and Improving the Reliability of Internet Last-mile Links

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People rely on having persistent Internet connectivity from their homes and

mobile devices. However, unlike links in the core of the Internet, the links

that connect people's homes and mobile devices, known as "last-mile" links, are

not redundant. As a result, the reliability of any given link is of paramount

concern: when last-mile links fail, people can be completely disconnected from

the Internet.

In addition to lacking redundancy, Internet last-mile links are vulnerable to

failure. Such links can fail because the cables and equipment that make up

last-mile links are exposed to the elements; for example, weather can cause

tree limbs to fall on overhead cables, and flooding can destroy underground

equipment. They can also fail, eventually, because cellular last-mile links can

drain a smartphone's battery if an application tries to communicate when signal

strength is weak.

In this dissertation, I defend the following thesis: By building on existing

infrastructure, it is possible to (1) observe the reliability of Internet

last-mile links across different weather conditions and link types; (2) improve

the energy efficiency of cellular Internet last-mile links; and (3) provide an

incrementally deployable, energy-efficient Internet last-mile downlink that is

highly resilient to weather-related failures. I defend this thesis by

designing, implementing, and evaluating systems.