A Retrospective on Campus Network Traffic Monitoring.

On April 1, 2023 we stopped monitoring the traffic on our campus Internet link, nearly 20 years to the day since we first started doing so. During these two decades, we faced a vast array of issues that affected the collection, storage, analysis and backup of our monitoring data. In this paper we share some of our experiences, so that future networking researchers have an opportunity to learn from our successes as well as our many mistakes and misfortunes.