ARPANET is short for "Advanced Research Projects Agency Network".
ARPANET is a term which can be broken down into two segments: ARPA
and NET. ARPA stands for the Advanced
Research Projects Agency; which is an agency within the United
States Department of Defense (Government department). ARPA was later
to be renamed DARPA, which stood for: Defense Advanced Research
ARPANET was one of the first 'wide area' computer networks, and
was created to allow US research laboratories and universities to
connect and exchange data. ARPANET was one of the first computer
networks to feature packet switching. Packet switching would underpin
how the Internet works. ARPANET is therefore viewed as a forerunner
to the Internet.
The Plan to build ARPANET
In the early 1960's one of the first scientists to formulate the
idea of a 'wide area' computer network was Joseph
Licklider. Licklider was the first director of the Information
Processing Techniques Office (IPTO) of ARPA in the early 1960's
and is often quoted as being the individual who inspired (later)
computer scientists (at ARPA) to develop ARPANET. In 1963, J Licklider
envisaged a 'Intergalactic (global) Network' which would use a standardised
computer language. While Licklider was not involved in creating
ARPANET (he had left ARPA), his influence was crucial in persuading
Ivan Sutherland and Robert Taylor that a 'wide area' network' was
of great importance.
In 1964, J Licklider was replaced as the director of the Information
Processing Techniques Office (IPTO) by Ivan Sutherland. In 1966,
Sutherland was replaced as the director of the IPTO by Robert
'Bob' Taylor. Robert Taylor had continued to pursue Licklider's
idea of a 'wide area' network, and, in 1966, Taylor received $1,000.000
in funding to build a 'wide area' computer network from Charles
Herzfeld (director of ARPA). In 1966, Taylor persuaded - through
the intervention of Herzfeld - Lawrence
'Larry' Roberts to leave MIT and build ARPA's computer network.
The theory underpinning ARPANET - packet switching - was outlined
in 1964 by a book 'Communication Nets' authored by Leonard
In 1967, Larry Roberts wrote a blue-print for ARPANET in a report
titled 'Multiple Computer Networks and Intercomputer Communications';
this blue-print would be based upon ideas previously outlined by
Leonard Kleinrock. Plans to build ARPANET began in 1967: specifically
at the "ARPANET Design
Session" in Ann Arbor, Michigan. It was at this meeting
that Wesley A. Clark would suggest the concept of Interface Message
Processors (IMPs) to Larry Roberts. Barry Wessler assisted Larry
Roberts in finalising the specification for the IMPs in August of
1967. E. B. Shapiro, who worked at the Stanford Research Institute,
authored a report titled 'A Study of Computer Network Design Parameters'
which aided Wessler and Roberts in defining their specification
for the IMP.
Larry Roberts, in 1968, sent a 'Request For Quotation' for the
development of the IMP to over 100 companies. ARPA eventually contracted
the work of building the IMP to 'Bolt,
Beranek and Newman' (BBN) technologies in 1968. The Interface
Message Processor was a micro-computer that functioned as a
packet-switching node; the IMP technology was outlined in the first
RFC document (RFC 1). Robert Kahn, whilst working for BBN, authored
'Host to IMP Spec. 1822' which outlined how to write an interface
so that host computers could connect to the IMP.
The task of writing the host-to-host protocols for ARPANET was
conducted by the Network Working Group (NWG) - a forerunner to the
Internet Engineering Task Force (IEFT). The NWG was led by Stephen
D. Crocker and supervised by Larry Roberts. It was Crocker who
invented the Request for Comments (RFC) document system - to better
handle the design process of the protocols - and who outlined the
original ARPANET protocols in RFC1, RFC2, RFC3 and RFC4. The starting
point for an ARPANET protocol was the 1822 protocol; this protocol
would eventually be replaced by the Network
Control Program (NCP) (designed by the NWG). The process of
creating the protocols, was, according to Stephen Crocker, a haphazard
process that did not adhere to a 'grand plan'.
The team of computer scientists who helped to design and build
ARPANET are known as the: Pioneers
of the Internet.
ARPANET is operational
The first test of the ARPANET network was conducted between 2 nodes:
one node was located a the University of California, Los Angeles
(UCLA), and the second node was located at the Stanford Research
Institute (SRI). Leonard Kleinrock and Douglas Engelbart, respectively,
installed the IMP at these academic institutions. The first message
that was sent on ARPANET was transmitted by Charles
S. Kline on the 29th of October, 1969.
When ARPANET was eventually launched, it was comprised of four
nodes; each node featured an Interface Message Processor (IMP).
The four nodes (locations) were:
- University of California, Los Angeles (UCLA)
- Stanford Research Institute (SRI)
- University of California, Santa Barbara (UCSB)
- University of Utah
As a side note: it may seem unusual for one of the nodes to be
located in Utah; the other nodes were located in California. Ivan
Sutherland, previously a director at the IPTO of ARPA - a keen supporter
for the funding of ARPANET - worked at the computer science department
at the University of Utah.
The first authority created for ARPANET was the Network
Information Center (NIC). The Network Information Center (NIC)
was located at Douglas Engelbart's Augmentation Research Center
(SRI) laboratory. Each host computer on the ARPANET was assigned
a number. The issue with numbers are that they are difficult to
memorise. Hostnames were devised to make it easy to memorise the
address of host computers connected to ARPANET. The Network Information
Center (NIC) was created to manage the process of assigning hostnames.
ARPANET nodes could request a hostname from the Network Information
Center (NIC). The NIC would manually store all the hostname information
in a file named: HOSTS.TXT. Hosts would
download this file from SRI and manually install it onto their host
computer. Eventually, the Domain Name System (DNS) would be created
(1984) to replace this system.
By 1973, ARPANET had been connected to over 25 nodes in the United
States of America, and it had been connected to it's first international
nodes (in Norway and England). The key individuals who developed
ARPANET, such as Bob Taylor, left ARPA in 1973. In 1973, the Mansfield
Amendment directed ARPA to spend less funding on science projects
and to focus on projects with a direct military use. While ARPANET
would continue to be funded, it's funding was limited, and many
of the computer scientists who created it moved to the private sector
to develop commercial computer products.
In 1975, due in part to the Mansfield Amendment of 1973, and the
fact ARPANET was operational - ARPA was a development agenecy -
the Defense Communication Agency (DCA) took operational control
of ARPANET. The Defense Communication Agency (DCA) split ARPANET
into a research and a military network. The military network was
named MILNET, while the research network was still referred to as
ARPANET. Longterm plans were to phase out the research ARPANET network.
Despite the turbulence surrounding the operational control of ARPANET,
the development of computer networking protocols was still being
funded by ARPA (renamed DARPA). ARPANET originally used the Network
Control Program (NCP). Bob Kahn joined DARPA in 1972, and had an
idea for an 'open' network architecture that would solve some drawbacks
of the NCP program. In 1973, Bob Kahn invited Vint Cerf to help
him develop his idea into a working protocol. Vint Cerf joined DARPA
in 1976, and the protocol he co-invented with Bob Kahn was the Transmission
Control Program. Eventually this program would evolve to become
TCP/IP. TCP/IP replaced NCP on ARPANET on the 1st of January, 1983;
a date that is viewed as being the day the Internet was born.
ARPANET was slowly decommisioned from 1985 to 1989: due to the
creation of NSFNET and the Federal Internet Exchange (FIX). The
FIX allowed federal networks, like MILNET, to connect to the NSFNET