Defense Data Network
Encyclopedia
The Defense Data Network (DDN) was a computer network
ing effort of the United States Department of Defense
from 1983 through 1995.
(DCA) took over operation of the ARPANET
as it became an operational tool instead of a research project. In 1983, plans for a new generation of the Automatic Digital Network
(Autodin II) were canceled. Instead, a separate network to connect military installations called MILNET
was split off the ARPANET. The ARPANET would be used as an Internet
backbone for researchers, but be slowly phased out. Both networks carried unclassified information, and were connected at a small number of points which would allow total separation in the event of an emergency.
The DCA used the Defense Data Network (DDN) as the program name for these network programs.
As a large-scale, private internet, the DDN provided Internet Protocol
connectivity across the United States
and to US military bases abroad. Throughout the 1980s it expanded as a set of four parallel military networks, each at a different security level. These networks transitioned to become the NIPRNET
, SIPRNET
, and JWICS networks in the 1990s.
The four DDN subnetworks were:
MILNET and DSNET 1 were common user networks, much like the public Internet, but DSNET 2 was dedicated to supporting the Worldwide Military Command and Control System
(WWMCCS) and DSNET 3 was dedicated to supporting the DOD Intelligence Information System (DODIIS).
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
ing effort of the United States Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...
from 1983 through 1995.
History
In 1975, the Defense Communication AgencyDefense Information Systems Agency
The Defense Information Systems Agency is a United States Department of Defense agency that provides information technology and communications support to the President, Vice President, Secretary of Defense, the military Services, and the Combatant Commands.As part of the Base Realignment and...
(DCA) took over operation of the ARPANET
ARPANET
The Advanced Research Projects Agency Network , was the world's first operational packet switching network and the core network of a set that came to compose the global Internet...
as it became an operational tool instead of a research project. In 1983, plans for a new generation of the Automatic Digital Network
Automatic Digital Network
The Automatic Digital Network System, known as AUTODIN or ADNS, is a legacy data communications service in the United States Department of Defense...
(Autodin II) were canceled. Instead, a separate network to connect military installations called MILNET
MILNET
In computer networking, MILNET was the name given to the part of the ARPANET internetwork designated for unclassified United States Department of Defense traffic....
was split off the ARPANET. The ARPANET would be used as an Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
backbone for researchers, but be slowly phased out. Both networks carried unclassified information, and were connected at a small number of points which would allow total separation in the event of an emergency.
The DCA used the Defense Data Network (DDN) as the program name for these network programs.
As a large-scale, private internet, the DDN provided Internet Protocol
Internet Protocol
The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
connectivity across the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and to US military bases abroad. Throughout the 1980s it expanded as a set of four parallel military networks, each at a different security level. These networks transitioned to become the NIPRNET
NIPRNet
The Non-secure Internet Protocol Router Network is used to exchange sensitive but unclassified information between "internal" users as well as providing users access to the Internet. NIPRNet is composed of Internet Protocol routers owned by the United States Department of Defense...
, SIPRNET
SIPRNet
The Secret Internet Protocol Router Network is "a system of interconnected computer networks used by the United States Department of Defense and the U.S. Department of State to transmit classified information by packet switching over the TCP/IP protocols in a 'completely secure' environment"...
, and JWICS networks in the 1990s.
The four DDN subnetworks were:
- Military Network (MILNET) for Unclassified traffic
- Defense Secure Network One (DSNET 1) for Secret traffic
- Defense Secure Network Two (DSNET 2) for Top Secret traffic
- Defense Secure Network Three (DSNET 3) for Top Secret/Sensitive Compartmented Information (TS/SCI)
MILNET and DSNET 1 were common user networks, much like the public Internet, but DSNET 2 was dedicated to supporting the Worldwide Military Command and Control System
Worldwide Military Command and Control System
The Worldwide Military Command and Control System was a military command and control system implemented for the command and control of the United States military. It was created in the days following the Cuban Missile Crisis...
(WWMCCS) and DSNET 3 was dedicated to supporting the DOD Intelligence Information System (DODIIS).