A Comprehensive History of SDN (Software-Defined Networking) from Its Origins to 2017

Recently I shared an article titled “Clarifying the Relationship Between NFV and SDN?” and received many readers’ feedback, prompting me to explore the history of SDN as a foundation for learning and sharing this technology.

SDN originated from the Clean Slate project led by Professor Nick McKeown at Stanford University. The article includes a group photo of the team, with one notable figure missing (the answer appears at the end).

Understanding SDN’s development requires knowing two things: (1) the definition, architecture, and key contributors that shaped SDN, and (2) the foundational technical ideas that SDN borrowed and built upon.

In 2006, Dr. Martin Casado proposed the logically centralized security solution SANE, opening the door to centralized control for security.

In 2007, building on SANE, Dr. Casado created the Ethane project, the precursor of SDN architecture and OpenFlow. The same year, Professors Nick McKeown, Scott Shenker, and Dr. Casado founded Nicira, the first SDN startup.

In 2008, eight scholars published the OpenFlow paper, and the Nick team released the first open‑source SDN controller NOX, marking the start of early SDN experimentation.

In 2009, SDN was listed among MIT Technology Review’s “Top 10 Breakthrough Technologies”. That year the Nick team released the Python controller POX, OpenFlow 1.0, and the open‑source network virtualization software FlowVisor. Nicira launched Open vSwitch, and Chinese entrepreneurs James Liao and Du Lin founded Pica8.

In 2010, the Nick team released Mininet. Google introduced the distributed SDN controller Onix, and former Stanford researchers founded BigSwitch. Princeton’s Jennifer Rexford’s group began focusing on SDN programming languages.

In 2011, the Open Networking Foundation (ONF) was created, and the first Open Networking Summit (ONS) was held. Nick McKeown, Scott Shenker, and Larry Peterson also founded the Open Networking Research Center (ONRC), the predecessor of ON.Lab.

2012 was a pivotal year: Google deployed the large‑scale SDN case B4, VMware acquired Nicira for $1.26 billion, and many Chinese SDN initiatives began. Notable releases included NoviFlow, the V330 switch from SENG, the Floodlight controller (the “mother” of ODL and ONOS), and NTT’s Ryu controller. The first HotSDN workshop was also held.

In 2013, the OpenDaylight project was launched, Cisco acquired Insieme and announced ACI, VMware released NSX, AT&T announced Domain 2.0, and SENG’s V350 won the first ONS SDN Idol award. Four of Nick’s PhD students founded Forward Networks, and another founded Barefoot.

In 2014, ONOS and the P4 language were introduced, Facebook opened the design of its Wedge switch via the OCP project, and white‑box switches became prominent. Cavium acquired SDN startup Xpliant, Broadcom released the OF‑DPA framework, and many comprehensive survey papers appeared, including “SDN: A Comprehensive Survey”. Huawei released the POF framework.

In 2015, ONF announced an open‑source SDN project community, SD‑WAN emerged as a mature SDN application market, and the convergence of SDN and NFV became a major trend.

In 2016, Chinese SDN startups such as CloudTree Networks and Dahe CloudLink secured funding, SENG raised 310 million RMB, and companies like VeloCloud, Plexxi, Cumulus, and BigSwitch received new investment rounds. IEEE organized an NFV‑SDN conference, and research on network programming languages gained significant academic attention. The SDN‑IoT academic workshop was also held.

Looking ahead to 2017, the future of SDN remains to be seen.

My personal view is that SDN’s history should be counted from the 2008 OpenFlow paper; over the past nine years, both academia and industry have jointly created a complete SDN development narrative, though each side followed distinct trajectories.

Academically, SDN’s progress resembles a parabola: early work was limited to Stanford’s team, peaked around 2012, and began to plateau after 2015.

In industry, growth has been rapid: starting with the 2012 acquisition wave and Google’s case, the market exploded into mature segments such as white‑box switches, network operating systems, data‑center network virtualization, and SD‑WAN, with many startups emerging. 2016 marked a year of recognition for Chinese SDN companies, and SDN is expected to expand into more domains over time.

The most impressive aspect is the Stanford team led by Nick McKeown, which achieved remarkable academic results, demonstrated keen insight in selecting research problems, and displayed deep technical expertise.

Equally notable is their ability to spin out multiple SDN startups, bridge academia and industry through open, nonprofit organizations, and earn widespread recognition across the networking industry.

The group photo at the beginning is missing Martin Casado, another outstanding contributor, as well as Professor Scott (Martin’s other mentor).

Author: Yang Zewei, OCSA trainer, author of “Zero‑Deposit NetFPGA Development Guide” and “Deep Understanding of Computer Network System Design”, co‑founder of SDN startup Nanjing DieSi, former senior principal engineer at ZTE Microelectronics, with extensive SDN industry and product experience.

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