They say brilliant minds think alike. That was certainly the case in 2001, when four different research groups simultaneously developed distributed hash tables (DHTs), the first data structures capable of operating at global scale. One of those pioneering systems—a Content-Addressable Network, or CAN—was spearheaded by researchers Sylvia Ratnasamy, Paul Francis, Mark Handley, Richard Karp, and Scott Shenker, members of ICSI’s (then) newly-established networking group. While none of the original DHT systems are currently in use, their invention eventually led to the NoSQL data stores that are widely used in modern data centers.
This story was published in January 2026 as part of a retrospective series highlighting ICSI’s accomplishments and impacts over the years. To learn about our ongoing work, explore our Core Research Themes.