The Software-Defined Networking (SDN) knowledge base provides a concise, yet comprehensive overview of the many technologies subsumed under the broad topic SDN, and collects in one place the lessons-learned by many individuals and companies that have deployed SDN or associated software architectures such as Network Functions Virtualization (NFV). The SDN knowledge base also provides supplemental information for those already using or planning to use SDN or associated software architectures.

Where to Begin

A first-time visitor to the SDN knowledge base might want to begin by reading the IntroductionWhat is a Software-Defined technology, and What is Virtualization sections at the beginning of the Software-Defined Overview article and then explore the Frequently Asked Questions article. 

SDN and Internet Protocol version 6 (IPv6)

There are 5 layers (or 4 if you don’t count the physical layer) in the Internet Protocol suite (also known as TCP/IP) that defines the conceptual model for the Internet. Updating the networking infrastructure at a site already connected to the Internet to include SDN along with associated software architectures, or deploying a networking infrastructure including SDN and associated software architectures at a site not previously connected to the Internet, does not require any changes at the Internet Protocol (IP) or lower layers nor does it create any IP packet format incompatibilities.

Consequently, a decades-long coordination effort between and among sites on the Internet is not needed (in stark contrast to the on-going world-wide IPv4 to Internet Protocol version 6 (IPv6) Internet transition, where such coordination efforts are essential). Such updates and deployments are already taking place at individual sites and can continue to occur in the United States and around the world in an uncoordinated fashion.

Because IPv4 has been the only IP for many years, existing software typically supports IPv4 (although this is less likely for software developed after 2016). Unless otherwise noted, specific software products mentioned in this Overview support IPv4 and have been informally determined, based on users’ experiences and developers’ statements, to also support IPv6. (Such lack of support for IPv6 by SDN software products is rare.) 

An added benefit of such updated or newly-deployed infrastructure is that it will be able to support IPv6, and it is important that SDN support IPv6, as this article explains. 

SDN and the Internet of Things (IoT)

SDN is an enabler of the IoT, as explained in this 2016 article.


Some user sites on the Defense Research and Engineering Network (DREN) started updating their existing local networking infrastructure to include SDN architecture in 2012. CenturyLink, Inc. offered SDN and NFV services to DREN since January 2017. In 2021, Verizon Business Network Services LLC began providing networking infrastructure and services to DREN, including a variety of SDN services .

To contribute an article to the SDN knowledge base, or to correct/update an existing article, please contact sdn-team [at] dren.mil.