This Defense Research and Engineering Network (DREN) 4 Performance Work Statement (PWS) was originally issued in Dec 2019, in order to continue providing state-of-the-art Wide Area Networking (WAN) services as a follow-on to the services provided under the DREN III PWS. The contract was awarded in May 2021 and will enable further expansion of the DREN WAN capability.

This DREN 4 PWS [PDF version] (Dod PKI required) provides details about the services and capabilities available under the contract.

Purpose

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 Introduction, What 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.

SDN and DREN

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.

Welcome

A first time visitor to the Internet Protocol version 6 (IPv6) Knowledge Base might want to begin by skimming the Purpose and Structure of the IPv6 Knowledge Base article in the IPv6 and IoT Frequently Asked Questions section and then explore the Initial Introduction article in the General Information section. 

Almost all unclassified computer networks around the world are interconnected via a worldwide computer network commonly referred to as the Internet which has been continuously expanding in size since the standardization of the Internet Protocol Suite in 1982. The functionality of the Internet has also been expanding. Examples of functionality expansion include:

1. The World Wide Web (WWW) began appearing on the Internet around 1991. This article describes its expansion.
2. Internet Protocol version 6 (IPv6) began appearing on the Internet beginning in 1999. This article provides a summary of IPv6 deployment efforts around the world.
3. When cloud computing began appearing on the Internet is hard to determine, due to its very nature, but it was on the Internet by 2000.
4. The Internet of Things (IoT) (which have also been called Smart Objects, Things, or Devices) began appearing on the Internet around 1999. This article describes its expansion. This article summarizes the advantages and benefits of IPv6 in the deployment of IoT. More than you may want to know about the ways in which the IoT is expanding the Internet can be found in this Internet of Things Connectivity Binge article.
5. Precursors to the Industrial IoT (IIoT) began appearing in 1962 under various names. The IIoT (and a related concept Industry 4.0) began appearing on the Internet in 2006. More than you may want to know about terms associated with IoT and IIoT can be found in this A-to-Z Guide To the Internet of Things article.
6. Software-Defined Networking (SDN) began appearing on the Internet around 2008. See this 2018 article for a description of its impact on the Internet.
7. Smart Cities began to be recognized in 2011. Both IPv6 and the IoT are essential enablers during the deployment of smart cities. See the Frequently Asked Questions (FAQ) Additional Information about IoT and Smart Cities article for more information.
8. Artificial Intelligence (AI) began to be recognized in 2017. See the Artificial Intelligence section of this 2017 Internet Society Paths to our Digital Future report for additional information.

While all of these have significantly expanded the capabilities of the Internet, only IPv6 has changed the process of interconnecting computers together to form networks along with the process of interconnecting networks around the world to expand the Internet.

IPv4 is over forty years old. This critical part of the Internet’s infrastructure is nearing its end of useful life, as the American Registry for Internet Numbers (ARIN) issued the last remaining IPv4 addresses in its free pool in September 2015. This won’t have a noticeable impact on the way most individuals use the Internet, but the exhaustion of IPv4 addresses and the effort to deploy IPv6 have both impacted the way United States Federal departments and agencies, state and local government organizations, academic institutions and commercial businesses use the Internet, as was described at length in 2020 by this article. An updated description of their impact was described at length in 2025 by this article.

Where to Begin

Whatever your area of interest in the on-going world-wide effort to deploy IPv6, please take a moment to skim through the Table of Contents of this Internet Engineering Task Force (IETF) Request for Comments (RFC) 9386 IPv6 Deployment Status document. Some of the numerous topics discussed therein may contain information you will find of interest. You might also be interested in the Internet Society’s (ISOC) Frequently Asked Questions (FAQ) on IPv6 Adoption and IPv4 exhaustion. This article also provides an overview of the status of IPv6 deployment around the world by country. They are all being actively maintained, so you might want to review them occasionally.

If you are of the opinion that you don’t need to deploy IPv6 on your network (or, at least don’t need to deploy it anytime soon), please take a look at the IPv6 Not Needed Here!?! article in the General Information section. You might also want to read this Why Doesn’t the Internet Migrate Entirely to IPv6? article.

If you are just starting to think about deploying IPv6 or in the early phases of a deployment, please take a look at the Before you Begin and Overview of Process articles in the Deployment section.

Additional IPv6 Knowledge Base highlights include:

1. IPv6 Training and Learning – free and commercial books and training sources
2. Overview of Lessons Learned Deploying IPv6 - a collection of lessons learned by those who have already deployed IPv6
3. IPv6 and IoT Security Best-practices – answers to and solutions for IPv6 security concerns
4. Where to Get IPv6 Addresses – who to ask and what to ask them
5. IPv6 and IoT Networking Standards – current networking standards and organizations that maintain them.

IPv6 and the Internet of Things (IoT)

IPv6 is an enabler of the IoT, as this article on an Institute of Electrical and Electronic Engineers (IEEE) website explains.

IPv6 and AI

This article and this article describe the growing importance of IPv6 in enabling the advancement of AI.

DREN and IPv6

The Defense Research and Engineering Network (DREN) started supporting IPv6 in June, 2003, when it was designated as the first Department of Defense (DoD) IPv6 pilot network by the Assistant Secretary of Defense (Networks and Information Integration)/DoD Chief Information Officer [ASD(NII)/DoD CIO]. By July, 2005, the entire DREN wide-area network was routinely supporting end-to-end IPv6 traffic, sites were supporting IPv6 along with IPv4, and selected applications were IPv6 enabled. DREN has provided its users with servers, services and client applications using IPv6 since then. During the worldwide deployment of IPv6, DREN will continue providing a secure, high-performance IPv6 infrastructure with legacy support for IPv4.

To contribute an article to the IPv6 Knowledge Base, or to correct/update an existing article, please contact ipv6-team [at] dren.mil.

Defense Research and Engineering Network (DREN) Customers are required to comply with documented policies and procedures. These policies have been developed as a result of Department of Defense (DoD) guidance and lessons-learned to ensure customer satisfaction, cybersecurity compliance, and overall network management efficiency. Networking policies apply to each enclave connecting to DREN and Secret Defense Research and Engineering Network (SDREN).

DREN policies define acceptable use, connection approval process, routing change procedures, Cybersecurity Service Provider (CSSP) requirements, exception request procedures for ports and protocols, and whitelist processes. These policies and others can be found in the DREN Service Agreement.

SDREN policies include acceptable use, connection approval process, routing change procedures, and CSSP requirements. These policies are defined in the SDREN Connection Approval Process (CAP) document.