All summer internships are about networking, but it’s a rare internship that starts a networking revolution. In the mid-2000s, Martín Casado, then a graduate student working with Nick McKeown at Stanford University, was spending a summer with ICSI’s networking group working with Vern Paxson when he approached Scott Shenker with an ambitious idea for enhancing network security. The idea sparked a remarkable collaboration between Casado, Shenker, and McKeown that ultimately led to a new paradigm for network management—Software Defined Networking (SDN). SDN provides a clean modularity for the network control plane, which then allows operators to have programmatic control over their networks.
Despite the idea’s clear promise, the team found no interest when they tried to give the technology away to networking vendors. To pursue commercialization themselves, the researchers founded a company, Nicira, in 2007. However, it took some time to find the right product-market fit. Their key breakthrough came with network virtualization, which allows individual customers in multitenant datacenters to create their own virtual networks. The technology has since become a multi-billion dollar business for VMWare, which acquired Nicira in 2012.
What made ICSI a good place to pursue these projects?
“ICSI provides tremendous flexibility, which has allowed the networking group to evolve our funding models (from the early AT&T support to government grants) and research focus (network security has played an increasing role in our research, while other areas have diminished). In addition, the close proximity to UC Berkeley gives researchers access to a broad set of collaborators. All of these factors make ICSI a great place to pursue innovative ideas.”
Scott Shenker
Principal Scientist and Co-Group Lead for Networked Systems, ICSI
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.