The U.S. National Science Foundation's Role in Enabling Software-Defined Networking

The commercial Internet grew quickly in the 1990s and early 2000s because it was relatively easy for network owners to connect interoperable equipment, such as routers, without relying on a central administrative authority.

However, a small number of router vendors controlled both the hardware and the software on these devices, leaving network owners with limited control over how their networks behave.

Adding new network capabilities required support from these vendors and a multi-year standardization process to ensure interoperability across vendors.

The result was bloated router software with tens of millions of lines of code, networks that were remarkably difficult to manage, and a frustratingly slow pace of innovation.