A Brief History of the Internet
Barry M. Leiner,
Vinton G. Cerf,
David D. Clark,
Robert E. Kahn,
Leonard Kleinrock,
Daniel C. Lynch,
Jon Postel,
Larry G. Roberts,
Stephen Wolff
Introduction
Origins of the Internet
The Initial Internetting
Concepts
Proving the Ideas
Transition to Widespread
Infrastructure
The Role of
Documentation
Formation of the Broad
Community
Commercialization of the
Technology
History of the Future
Footnotes
Timeline
References
Authors
Introduction
The Internet has revolutionized the computer and
communications world like nothing before. The invention
of the telegraph, telephone, radio, and computer set the
stage for this unprecedented integration of capabilities.
The Internet is at once a world-wide broadcasting
capability, a mechanism for information dissemination,
and a medium for collaboration and interaction between
individuals and their computers without regard for
geographic location.
The Internet represents one of the most successful
examples of the benefits of sustained investment and
commitment to research and development of information
infrastructure. Beginning with the early research in
packet switching, the government, industry and academia
have been partners in evolving and deploying this
exciting new technology. Today, terms like
"bleiner@computer.org" and "http://www.acm.org" trip
lightly off the tongue of the random person on the
street. 1
This is intended to be a brief, necessarily cursory
and incomplete history. Much material currently exists
about the Internet, covering history, technology, and
usage. A trip to almost any bookstore will find shelves
of material written about the Internet. 2
In this paper, 3
several of us involved in the development and evolution
of the Internet share our views of its origins and
history. This history revolves around four distinct
aspects. There is the technological evolution that began
with early research on packet switching and the ARPANET
(and related technologies), and where current research
continues to expand the horizons of the infrastructure
along several dimensions, such as scale, performance, and
higher level functionality. There is the operations and
management aspect of a global and complex operational
infrastructure. There is the social aspect, which
resulted in a broad community of Internauts
working together to create and evolve the technology. And
there is the commercialization aspect, resulting in an
extremely effective transition of research results into a
broadly deployed and available information
infrastructure.
The Internet today is a widespread information
infrastructure, the initial prototype of what is often
called the National (or Global or Galactic) Information
Infrastructure. Its history is complex and involves many
aspects - technological, organizational, and community.
And its influence reaches not only to the technical
fields of computer communications but throughout society
as we move toward increasing use of online tools to
accomplish electronic commerce, information acquisition,
and community operations.
Origins of the Internet
The first recorded description of the social
interactions that could be enabled through networking was
a series of memos written by J.C.R.
Licklider of MIT in August 1962 discussing his "Galactic
Network" concept. He envisioned a globally interconnected
set of computers through which everyone could quickly
access data and programs from any site. In spirit, the
concept was very much like the Internet of today.
Licklider was the first head of the computer research
program at DARPA, 4
starting in October 1962. While at DARPA he convinced his
successors at DARPA, Ivan Sutherland, Bob Taylor, and MIT
researcher Lawrence G. Roberts, of the importance of this
networking concept.
Leonard Kleinrock at MIT published the first
paper on packet switching theory in July 1961 and the
first book on the subject in 1964.
Kleinrock convinced Roberts of the theoretical
feasibility of communications using packets rather than
circuits, which was a major step along the path towards
computer networking. The other key step was to make the
computers talk together. To explore this, in 1965 working
with Thomas Merrill, Roberts connected the TX-2 computer
in Mass. to the Q-32 in California with a low speed
dial-up telephone line creating the first
(however small) wide-area computer network ever
built. The result of this experiment was the
realization that the time-shared computers could work
well together, running programs and retrieving data as
necessary on the remote machine, but that the circuit
switched telephone system was totally inadequate for the
job. Kleinrock's conviction of the need for packet
switching was confirmed.
In late 1966 Roberts went to DARPA to develop the
computer network concept and quickly put together his
plan for the "ARPANET", publishing
it in 1967. At the conference where he presented the
paper, there was also a paper on a packet network concept
from the UK by Donald Davies and Roger Scantlebury of
NPL. Scantlebury told Roberts about the NPL work as well
as that of Paul Baran and others at RAND. The RAND group
had written a paper on packet switching
networks for secure voice in the military in 1964. It
happened that the work at MIT (1961-1967), at RAND
(1962-1965), and at NPL (1964-1967) had all proceeded in
parallel without any of the researchers knowing about the
other work. The word "packet" was adopted from the work
at NPL and the proposed line speed to be used in the
ARPANET design was upgraded from 2.4 kbps to 50 kbps.
5
In August 1968, after Roberts and the DARPA funded
community had refined the overall structure and
specifications for the ARPANET, an RFQ was released by
DARPA for the development of one of the key components,
the packet switches called Interface Message Processors
(IMP's). The RFQ was won in December 1968 by a group
headed by Frank Heart at Bolt Beranek and Newman (BBN).
As the BBN team worked on the IMP's with Bob Kahn playing
a major role in the overall ARPANET architectural design,
the network topology and economics were designed and
optimized by Roberts working with Howard Frank and his
team at Network Analysis Corporation, and the network
measurement system was prepared by Kleinrock's team at
UCLA. 6
Due to Kleinrock's early development of packet
switching theory and his focus on analysis, design and
measurement, his Network Measurement Center at UCLA was
selected to be the first node on the ARPANET. All this
came together in September 1969 when BBN installed the
first IMP at UCLA and the first host computer was
connected. Doug Engelbart's project on "Augmentation of
Human Intellect" (which included NLS, an early hypertext
system) at Stanford Research Institute (SRI) provided a
second node. SRI supported the Network Information
Center, led by Elizabeth (Jake) Feinler and including
functions such as maintaining tables of host name to
address mapping as well as a directory of the RFC's. One
month later, when SRI was connected to the ARPANET, the
first host-to-host message was sent from Kleinrock's
laboratory to SRI. Two more nodes were added at UC Santa
Barbara and University of Utah. These last two nodes
incorporated application visualization projects, with
Glen Culler and Burton Fried at UCSB investigating
methods for display of mathematical functions using
storage displays to deal with the problem of refresh over
the net, and Robert Taylor and Ivan Sutherland at Utah
investigating methods of 3-D representations over the
net. Thus, by the end of 1969, four host computers were
connected together into the initial ARPANET, and the
budding Internet was off the ground. Even at this early
stage, it should be noted that the networking research
incorporated both work on the underlying network and work
on how to utilize the network. This tradition continues
to this day.
Computers were added quickly to the ARPANET during the
following years, and work proceeded on completing a
functionally complete Host-to-Host protocol and other
network software. In December 1970 the Network Working
Group (NWG) working under S. Crocker finished the initial
ARPANET Host-to-Host protocol, called the Network Control
Protocol (NCP). As the ARPANET sites completed
implementing NCP during the period 1971-1972, the network
users finally could begin to develop applications.
In October 1972 Kahn organized a large, very
successful demonstration of the ARPANET at the
International Computer Communication Conference (ICCC).
This was the first public demonstration of this new
network technology to the public. It was also in 1972
that the initial "hot" application, electronic mail, was
introduced. In March Ray Tomlinson at BBN wrote the basic
email message send and read software, motivated by the
need of the ARPANET developers for an easy coordination
mechanism. In July, Roberts expanded its utility by
writing the first email utility program to list,
selectively read, file, forward, and respond to messages.
From there email took off as the largest network
application for over a decade. This was a harbinger of
the kind of activity we see on the World Wide Web today,
namely, the enormous growth of all kinds of
"people-to-people" traffic.
The Initial Internetting Concepts
The original ARPANET grew into the Internet. Internet
was based on the idea that there would be multiple
independent networks of rather arbitrary design,
beginning with the ARPANET as the pioneering packet
switching network, but soon to include packet satellite
networks, ground-based packet radio networks and other
networks. The Internet as we now know it embodies a key
underlying technical idea, namely that of open
architecture networking. In this approach, the choice of
any individual network technology was not dictated by a
particular network architecture but rather could be
selected freely by a provider and made to interwork with
the other networks through a meta-level "Internetworking
Architecture". Up until that time there was only one
general method for federating networks. This was the
traditional circuit switching method where networks would
interconnect at the circuit level, passing individual
bits on a synchronous basis along a portion of an
end-to-end circuit between a pair of end locations.
Recall that Kleinrock had shown in 1961 that packet
switching was a more efficient switching method. Along
with packet switching, special purpose interconnection
arrangements between networks were another possibility.
While there were other limited ways to interconnect
different networks, they required that one be used as a
component of the other, rather than acting as a
peer of the other in offering end-to-end
service.
In an open-architecture network, the individual
networks may be separately designed and developed and
each may have its own unique interface which it may offer
to users and/or other providers. including other Internet
providers. Each network can be designed in accordance
with the specific environment and user requirements of
that network. There are generally no constraints on the
types of network that can be included or on their
geographic scope, although certain pragmatic
considerations will dictate what makes sense to
offer.
The idea of open-architecture networking was first
introduced by Kahn shortly after having arrived at DARPA
in 1972. This work was originally part of the packet
radio program, but subsequently became a separate program
in its own right. At the time, the program was called
"Internetting". Key to making the packet radio system
work was a reliable end-end protocol that could maintain
effective communication in the face of jamming and other
radio interference, or withstand intermittent blackout
such as caused by being in a tunnel or blocked by the
local terrain. Kahn first contemplated developing a
protocol local only to the packet radio network, since
that would avoid having to deal with the multitude of
different operating systems, and continuing to use
NCP.
However, NCP did not have the ability to address
networks (and machines) further downstream than a
destination IMP on the ARPANET and thus some change to
NCP would also be required. (The assumption was that the
ARPANET was not changeable in this regard). NCP relied on
ARPANET to provide end-to-end reliability. If any packets
were lost, the protocol (and presumably any applications
it supported) would come to a grinding halt. In this
model NCP had no end-end host error control, since the
ARPANET was to be the only network in existence and it
would be so reliable that no error control would be
required on the part of the hosts.
Thus, Kahn decided to develop a new version of the
protocol which could meet the needs of an
open-architecture network environment. This protocol
would eventually be called the Transmission Control
Protocol/Internet Protocol (TCP/IP). While NCP tended to
act like a device driver, the new protocol would be more
like a communications protocol.
Four ground rules were critical to Kahn's early
thinking:
- Each distinct network would have to stand on its
own and no internal changes could be required to any
such network to connect it to the Internet.
- Communications would be on a best effort basis. If
a packet didn't make it to the final destination, it
would shortly be retransmitted from the source.
- Black boxes would be used to connect the networks;
these would later be called gateways and routers.
There would be no information retained by the gateways
about the individual flows of packets passing through
them, thereby keeping them simple and avoiding
complicated adaptation and recovery from various
failure modes.
- There would be no global control at the operations
level.
Other key issues that needed to be addressed were:
- Algorithms to prevent lost packets from
permanently disabling communications and enabling them
to be successfully retransmitted from the source.
- Providing for host to host "pipelining" so that
multiple packets could be enroute from source to
destination at the discretion of the participating
hosts, if the intermediate networks allowed it.
- Gateway functions to allow it to forward packets
appropriately. This included interpreting IP headers
for routing, handling interfaces, breaking packets
into smaller pieces if necessary, etc.
- The need for end-end checksums, reassembly of
packets from fragments and detection of duplicates, if
any.
- The need for global addressing
- Techniques for host to host flow control.
- Interfacing with the various operating systems
- There were also other concerns, such as
implementation efficiency, internetwork performance,
but these were secondary considerations at first.
Kahn began work on a communications-oriented set of
operating system principles while at BBN and documented
some of his early thoughts in an internal BBN memorandum
entitled "Communications Principles for
Operating Systems". At this point he realized it
would be necessary to learn the implementation details of
each operating system to have a chance to embed any new
protocols in an efficient way. Thus, in the spring of
1973, after starting the internetting effort, he asked
Vint Cerf (then at Stanford) to work with him on the
detailed design of the protocol. Cerf had been intimately
involved in the original NCP design and development and
already had the knowledge about interfacing to existing
operating systems. So armed with Kahn's architectural
approach to the communications side and with Cerf's NCP
experience, they teamed up to spell out the details of
what became TCP/IP.
The give and take was highly productive and the first
written version 7 of the
resulting approach was distributed at a special meeting
of the International Network Working Group (INWG) which
had been set up at a conference at Sussex University in
September 1973. Cerf had been invited to chair this group
and used the occasion to hold a meeting of INWG members
who were heavily represented at the Sussex
Conference.
Some basic approaches emerged from this collaboration
between Kahn and Cerf:
- Communication between two processes would
logically consist of a very long stream of bytes (they
called them octets). The position of any octet in the
stream would be used to identify it.
- Flow control would be done by using sliding
windows and acknowledgments (acks). The destination
could select when to acknowledge and each ack returned
would be cumulative for all packets received to that
point.
- It was left open as to exactly how the source and
destination would agree on the parameters of the
windowing to be used. Defaults were used
initially.
- Although Ethernet was under development at Xerox
PARC at that time, the proliferation of LANs were not
envisioned at the time, much less PCs and
workstations. The original model was national level
networks like ARPANET of which only a relatively small
number were expected to exist. Thus a 32 bit IP
address was used of which the first 8 bits signified
the network and the remaining 24 bits designated the
host on that network. This assumption, that 256
networks would be sufficient for the foreseeable
future, was clearly in need of reconsideration when
LANs began to appear in the late 1970s.
The original Cerf/Kahn paper on the Internet described
one protocol, called TCP, which provided all the
transport and forwarding services in the Internet. Kahn
had intended that the TCP protocol support a range of
transport services, from the totally reliable sequenced
delivery of data (virtual circuit model) to a
datagram service in which the application made
direct use of the underlying network service, which might
imply occasional lost, corrupted or reordered
packets.
However, the initial effort to implement TCP resulted
in a version that only allowed for virtual circuits. This
model worked fine for file transfer and remote login
applications, but some of the early work on advanced
network applications, in particular packet voice in the
1970s, made clear that in some cases packet losses should
not be corrected by TCP, but should be left to the
application to deal with. This led to a reorganization of
the original TCP into two protocols, the simple IP which
provided only for addressing and forwarding of individual
packets, and the separate TCP, which was concerned with
service features such as flow control and recovery from
lost packets. For those applications that did not want
the services of TCP, an alternative called the User
Datagram Protocol (UDP) was added in order to provide
direct access to the basic service of IP.
A major initial motivation for both the ARPANET and
the Internet was resource sharing - for example allowing
users on the packet radio networks to access the time
sharing systems attached to the ARPANET. Connecting the
two together was far more economical that duplicating
these very expensive computers. However, while file
transfer and remote login (Telnet) were very important
applications, electronic mail has probably had the most
significant impact of the innovations from that era.
Email provided a new model of how people could
communicate with each other, and changed the nature of
collaboration, first in the building of the Internet
itself (as is discussed below) and later for much of
society.
There were other applications proposed in the early
days of the Internet, including packet based voice
communication (the precursor of Internet telephony),
various models of file and disk sharing, and early "worm"
programs that showed the concept of agents (and, of
course, viruses). A key concept of the Internet is that
it was not designed for just one application, but as a
general infrastructure on which new applications could be
conceived, as illustrated later by the emergence of the
World Wide Web. It is the general purpose nature of the
service provided by TCP and IP that makes this
possible.
Proving the Ideas
DARPA let three contracts to Stanford (Cerf), BBN (Ray
Tomlinson) and UCL (Peter Kirstein) to implement TCP/IP
(it was simply called TCP in the Cerf/Kahn paper but
contained both components). The Stanford team, led by
Cerf, produced the detailed specification and within
about a year there were three independent implementations
of TCP that could interoperate.
This was the beginning of long term experimentation
and development to evolve and mature the Internet
concepts and technology. Beginning with the first three
networks (ARPANET, Packet Radio, and Packet Satellite)
and their initial research communities, the experimental
environment has grown to incorporate essentially every
form of network and a very broad-based research and
development community. [REK78]
With each expansion has come new challenges.
The early implementations of TCP were done for large
time sharing systems such as Tenex and TOPS 20. When
desktop computers first appeared, it was thought by some
that TCP was too big and complex to run on a personal
computer. David Clark and his research group at MIT set
out to show that a compact and simple implementation of
TCP was possible. They produced an implementation, first
for the Xerox Alto (the early personal workstation
developed at Xerox PARC) and then for the IBM PC. That
implementation was fully interoperable with other TCPs,
but was tailored to the application suite and performance
objectives of the personal computer, and showed that
workstations, as well as large time-sharing systems,
could be a part of the Internet. In 1976, Kleinrock
published the first book on the
ARPANET. It included an emphasis on the complexity of
protocols and the pitfalls they often introduce. This
book was influential in spreading the lore of packet
switching networks to a very wide community.
Widespread development of LANS, PCs and workstations
in the 1980s allowed the nascent Internet to flourish.
Ethernet technology, developed by Bob Metcalfe at Xerox
PARC in 1973, is now probably the dominant network
technology in the Internet and PCs and workstations the
dominant computers. This change from having a few
networks with a modest number of time-shared hosts (the
original ARPANET model) to having many networks has
resulted in a number of new concepts and changes to the
underlying technology. First, it resulted in the
definition of three network classes (A, B, and C) to
accommodate the range of networks. Class A represented
large national scale networks (small number of networks
with large numbers of hosts); Class B represented
regional scale networks; and Class C represented local
area networks (large number of networks with relatively
few hosts).
A major shift occurred as a result of the increase in
scale of the Internet and its associated management
issues. To make it easy for people to use the network,
hosts were assigned names, so that it was not necessary
to remember the numeric addresses. Originally, there were
a fairly limited number of hosts, so it was feasible to
maintain a single table of all the hosts and their
associated names and addresses. The shift to having a
large number of independently managed networks (e.g.,
LANs) meant that having a single table of hosts was no
longer feasible, and the Domain Name System (DNS) was
invented by Paul Mockapetris of USC/ISI. The DNS
permitted a scalable distributed mechanism for resolving
hierarchical host names (e.g. www.acm.org) into an
Internet address.
The increase in the size of the Internet also
challenged the capabilities of the routers. Originally,
there was a single distributed algorithm for routing that
was implemented uniformly by all the routers in the
Internet. As the number of networks in the Internet
exploded, this initial design could not expand as
necessary, so it was replaced by a hierarchical model of
routing, with an Interior Gateway Protocol (IGP) used
inside each region of the Internet, and an Exterior
Gateway Protocol (EGP) used to tie the regions together.
This design permitted different regions to use a
different IGP, so that different requirements for cost,
rapid reconfiguration, robustness and scale could be
accommodated. Not only the routing algorithm, but the
size of the addressing tables, stressed the capacity of
the routers. New approaches for address aggregation, in
particular classless inter-domain routing (CIDR), have
recently been introduced to control the size of router
tables.
As the Internet evolved, one of the major challenges
was how to propagate the changes to the software,
particularly the host software. DARPA supported UC
Berkeley to investigate modifications to the Unix
operating system, including incorporating TCP/IP
developed at BBN. Although Berkeley later rewrote the BBN
code to more efficiently fit into the Unix system and
kernel, the incorporation of TCP/IP into the Unix BSD
system releases proved to be a critical element in
dispersion of the protocols to the research community.
Much of the CS research community began to use Unix BSD
for their day-to-day computing environment. Looking back,
the strategy of incorporating Internet protocols into a
supported operating system for the research community was
one of the key elements in the successful widespread
adoption of the Internet.
One of the more interesting challenges was the
transition of the ARPANET host protocol from NCP to
TCP/IP as of January 1, 1983. This was a "flag-day" style
transition, requiring all hosts to convert simultaneously
or be left having to communicate via rather ad-hoc
mechanisms. This transition was carefully planned within
the community over several years before it actually took
place and went surprisingly smoothly (but resulted in a
distribution of buttons saying "I survived the TCP/IP
transition").
TCP/IP was adopted as a defense standard three years
earlier in 1980. This enabled defense to begin sharing in
the DARPA Internet technology base and led directly to
the eventual partitioning of the military and non-
military communities. By 1983, ARPANET was being used by
a significant number of defense R&D and operational
organizations. The transition of ARPANET from NCP to
TCP/IP permitted it to be split into a MILNET supporting
operational requirements and an ARPANET supporting
research needs.
Thus, by 1985, Internet was already well established
as a technology supporting a broad community of
researchers and developers, and was beginning to be used
by other communities for daily computer communications.
Electronic mail was being used broadly across several
communities, often with different systems, but
interconnection between different mail systems was
demonstrating the utility of broad based electronic
communications between people.
Transition to Widespread Infrastructure
At the same time that the Internet technology was
being experimentally validated and widely used amongst a
subset of computer science researchers, other networks
and networking technologies were being pursued. The
usefulness of computer networking - especially electronic
mail - demonstrated by DARPA and Department of Defense
contractors on the ARPANET was not lost on other
communities and disciplines, so that by the mid-1970s
computer networks had begun to spring up wherever funding
could be found for the purpose. The U.S. Department of
Energy (DoE) established MFENet for its researchers in
Magnetic Fusion Energy, whereupon DoE's High Energy
Physicists responded by building HEPNet. NASA Space
Physicists followed with SPAN, and Rick Adrion, David
Farber, and Larry Landweber established CSNET for the
(academic and industrial) Computer Science community with
an initial grant from the U.S. National Science
Foundation (NSF). AT&T's free-wheeling dissemination
of the UNIX computer operating system spawned USENET,
based on UNIX' built-in UUCP communication protocols, and
in 1981 Ira Fuchs and Greydon Freeman devised BITNET,
which linked academic mainframe computers in an "email as
card images" paradigm.
With the exception of BITNET and USENET, these early
networks (including ARPANET) were purpose-built - i.e.,
they were intended for, and largely restricted to, closed
communities of scholars; there was hence little pressure
for the individual networks to be compatible and, indeed,
they largely were not. In addition, alternate
technologies were being pursued in the commercial sector,
including XNS from Xerox, DECNet, and IBM's SNA.
8 It remained for the
British JANET (1984) and U.S. NSFNET (1985) programs to
explicitly announce their intent to serve the entire
higher education community, regardless of discipline.
Indeed, a condition for a U.S. university to receive NSF
funding for an Internet connection was that "... the
connection must be made available to ALL qualified users
on campus."
In 1985, Dennis Jennings came from Ireland to spend a
year at NSF leading the NSFNET program. He worked with
the community to help NSF make a critical decision - that
TCP/IP would be mandatory for the NSFNET program. When
Steve Wolff took over the NSFNET program in 1986, he
recognized the need for a wide area networking
infrastructure to support the general academic and
research community, along with the need to develop a
strategy for establishing such infrastructure on a basis
ultimately independent of direct federal funding.
Policies and strategies were adopted (see below) to
achieve that end.
NSF also elected to support DARPA's existing Internet
organizational infrastructure, hierarchically arranged
under the (then) Internet Activities Board (IAB). The
public declaration of this choice was the joint
authorship by the IAB's Internet Engineering and
Architecture Task Forces and by NSF's Network Technical
Advisory Group of RFC 985 (Requirements for Internet
Gateways ), which formally ensured interoperability of
DARPA's and NSF's pieces of the Internet.
In addition to the selection of TCP/IP for the NSFNET
program, Federal agencies made and implemented several
other policy decisions which shaped the Internet of
today.
- Federal agencies shared the cost of common
infrastructure, such as trans-oceanic circuits. They
also jointly supported "managed interconnection
points" for interagency traffic; the Federal Internet
Exchanges (FIX-E and FIX-W) built for this purpose
served as models for the Network Access Points and
"*IX" facilities that are prominent features of
today's Internet architecture.
- To coordinate this sharing, the Federal Networking
Council 9 was formed.
The FNC also cooperated with other international
organizations, such as RARE in Europe, through the
Coordinating Committee on Intercontinental Research
Networking, CCIRN, to coordinate Internet support of
the research community worldwide.
- This sharing and cooperation between agencies on
Internet-related issues had a long history. An
unprecedented 1981 agreement between Farber, acting
for CSNET and the NSF, and DARPA's Kahn, permitted
CSNET traffic to share ARPANET infrastructure on a
statistical and no-metered-settlements basis.
- Subsequently, in a similar mode, the NSF
encouraged its regional (initially academic) networks
of the NSFNET to seek commercial, non-academic
customers, expand their facilities to serve them, and
exploit the resulting economies of scale to lower
subscription costs for all.
- On the NSFNET Backbone - the national-scale
segment of the NSFNET - NSF enforced an "Acceptable
Use Policy" (AUP) which prohibited Backbone usage for
purposes "not in support of Research and Education."
The predictable (and intended) result of encouraging
commercial network traffic at the local and regional
level, while denying its access to national-scale
transport, was to stimulate the emergence and/or
growth of "private", competitive, long-haul networks
such as PSI, UUNET, ANS CO+RE, and (later) others.
This process of privately-financed augmentation for
commercial uses was thrashed out starting in 1988 in a
series of NSF-initiated conferences at Harvard's
Kennedy School of Government on "The Commercialization
and Privatization of the Internet" - and on the
"com-priv" list on the net itself.
- In 1988, a National Research Council committee,
chaired by Kleinrock and with Kahn and Clark as
members, produced a report commissioned by NSF titled
"Towards a National Research Network". This report was
influential on then Senator Al Gore, and ushered in
high speed networks that laid the networking
foundation for the future information
superhighway.
- In 1994, a National Research Council report, again
chaired by Kleinrock (and with Kahn and Clark as
members again), Entitled "Realizing The Information
Future: The Internet and Beyond" was released. This
report, commissioned by NSF, was the document in which
a blueprint for the evolution of the information
superhighway was articulated and which has had a
lasting affect on the way to think about its
evolution. It anticipated the critical issues of
intellectual property rights, ethics, pricing,
education, architecture and regulation for the
Internet.
- NSF's privatization policy culminated in April,
1995, with the defunding of the NSFNET Backbone. The
funds thereby recovered were (competitively)
redistributed to regional networks to buy
national-scale Internet connectivity from the now
numerous, private, long-haul networks.
The backbone had made the transition from a network
built from routers out of the research community (the
"Fuzzball" routers from David Mills) to commercial
equipment. In its 8 1/2 year lifetime, the Backbone had
grown from six nodes with 56 kbps links to 21 nodes with
multiple 45 Mbps links. It had seen the Internet grow to
over 50,000 networks on all seven continents and outer
space, with approximately 29,000 networks in the United
States.
Such was the weight of the NSFNET program's ecumenism
and funding ($200 million from 1986 to 1995) - and the
quality of the protocols themselves - that by 1990 when
the ARPANET itself was finally decommissioned10,
TCP/IP had supplanted or marginalized most other
wide-area computer network protocols worldwide, and IP
was well on its way to becoming THE bearer service for
the Global Information Infrastructure.
The Role of Documentation
A key to the rapid growth of the Internet has been the
free and open access to the basic documents, especially
the specifications of the protocols.
The beginnings of the ARPANET and the Internet in the
university research community promoted the academic
tradition of open publication of ideas and results.
However, the normal cycle of traditional academic
publication was too formal and too slow for the dynamic
exchange of ideas essential to creating networks.
In 1969 a key step was taken by S. Crocker (then at
UCLA) in establishing the Request for
Comments (or RFC) series of notes. These memos were
intended to be an informal fast distribution way to share
ideas with other network researchers. At first the RFCs
were printed on paper and distributed via snail mail. As
the File Transfer Protocol (FTP) came into use, the RFCs
were prepared as online files and accessed via FTP. Now,
of course, the RFCs are easily accessed via the World
Wide Web at dozens of sites around the world. SRI, in its
role as Network Information Center, maintained the online
directories. Jon Postel acted as RFC Editor as well as
managing the centralized administration of required
protocol number assignments, roles that he continues to
this day.
The effect of the RFCs was to create a positive
feedback loop, with ideas or proposals presented in one
RFC triggering another RFC with additional ideas, and so
on. When some consensus (or a least a consistent set of
ideas) had come together a specification document would
be prepared. Such a specification would then be used as
the base for implementations by the various research
teams.
Over time, the RFCs have become more focused on
protocol standards (the "official" specifications),
though there are still informational RFCs that describe
alternate approaches, or provide background information
on protocols and engineering issues. The RFCs are now
viewed as the "documents of record" in the Internet
engineering and standards community.
The open access to the RFCs (for free, if you have any
kind of a connection to the Internet) promotes the growth
of the Internet because it allows the actual
specifications to be used for examples in college classes
and by entrepreneurs developing new systems.
Email has been a significant factor in all areas of
the Internet, and that is certainly true in the
development of protocol specifications, technical
standards, and Internet engineering. The very early RFCs
often presented a set of ideas developed by the
researchers at one location to the rest of the community.
After email came into use, the authorship pattern changed
- RFCs were presented by joint authors with common view
independent of their locations.
The use of specialized email mailing lists has been
long used in the development of protocol specifications,
and continues to be an important tool. The IETF now has
in excess of 75 working groups, each working on a
different aspect of Internet engineering. Each of these
working groups has a mailing list to discuss one or more
draft documents under development. When consensus is
reached on a draft document it may be distributed as an
RFC.
As the current rapid expansion of the Internet is
fueled by the realization of its capability to promote
information sharing, we should understand that the
network's first role in information sharing was sharing
the information about it's own design and operation
through the RFC documents. This unique method for
evolving new capabilities in the network will continue to
be critical to future evolution of the Internet.
Formation of the Broad Community
The Internet is as much a collection of communities as
a collection of technologies, and its success is largely
attributable to both satisfying basic community needs as
well as utilizing the community in an effective way to
push the infrastructure forward. This community spirit
has a long history beginning with the early ARPANET. The
early ARPANET researchers worked as a close-knit
community to accomplish the initial demonstrations of
packet switching technology described earlier. Likewise,
the Packet Satellite, Packet Radio and several other
DARPA computer science research programs were
multi-contractor collaborative activities that heavily
used whatever available mechanisms there were to
coordinate their efforts, starting with electronic mail
and adding file sharing, remote access, and eventually
World Wide Web capabilities. Each of these programs
formed a working group, starting with the ARPANET Network
Working Group. Because of the unique role that ARPANET
played as an infrastructure supporting the various
research programs, as the Internet started to evolve, the
Network Working Group evolved into Internet Working
Group.
In the late 1970's, recognizing that the growth of the
Internet was accompanied by a growth in the size of the
interested research community and therefore an increased
need for coordination mechanisms, Vint Cerf, then manager
of the Internet Program at DARPA, formed several
coordination bodies - an International Cooperation Board
(ICB), chaired by Peter Kirstein of UCL, to coordinate
activities with some cooperating European countries
centered on Packet Satellite research, an Internet
Research Group which was an inclusive group providing an
environment for general exchange of information, and an
Internet Configuration Control Board (ICCB), chaired by
Clark. The ICCB was an invitational body to assist Cerf
in managing the burgeoning Internet activity.
In 1983, when Barry Leiner took over management of the
Internet research program at DARPA, he and Clark
recognized that the continuing growth of the Internet
community demanded a restructuring of the coordination
mechanisms. The ICCB was disbanded and in its place a
structure of Task Forces was formed, each focused on a
particular area of the technology (e.g. routers,
end-to-end protocols, etc.). The Internet Activities
Board (IAB) was formed from the chairs of the Task
Forces. It of course was only a coincidence that the
chairs of the Task Forces were the same people as the
members of the old ICCB, and Dave Clark continued to act
as chair.
After some changing membership on the IAB, Phill Gross
became chair of a revitalized Internet Engineering Task
Force (IETF), at the time merely one of the IAB Task
Forces. As we saw above, by 1985 there was a tremendous
growth in the more practical/engineering side of the
Internet. This growth resulted in an explosion in the
attendance at the IETF meetings, and Gross was compelled
to create substructure to the IETF in the form of working
groups.
This growth was complemented by a major expansion in
the community. No longer was DARPA the only major player
in the funding of the Internet. In addition to NSFNet and
the various US and international government-funded
activities, interest in the commercial sector was
beginning to grow. Also in 1985, both Kahn and Leiner
left DARPA and there was a significant decrease in
Internet activity at DARPA. As a result, the IAB was left
without a primary sponsor and increasingly assumed the
mantle of leadership.
The growth continued, resulting in even further
substructure within both the IAB and IETF. The IETF
combined Working Groups into Areas, and designated Area
Directors. An Internet Engineering Steering Group (IESG)
was formed of the Area Directors. The IAB recognized the
increasing importance of the IETF, and restructured the
standards process to explicitly recognize the IESG as the
major review body for standards. The IAB also
restructured so that the rest of the Task Forces (other
than the IETF) were combined into an Internet Research
Task Force (IRTF) chaired by Postel, with the old task
forces renamed as research groups.
The growth in the commercial sector brought with it
increased concern regarding the standards process itself.
Starting in the early 1980's and continuing to this day,
the Internet grew beyond its primarily research roots to
include both a broad user community and increased
commercial activity. Increased attention was paid to
making the process open and fair. This coupled with a
recognized need for community support of the Internet
eventually led to the formation of the Internet Society
in 1991, under the auspices of Kahn's Corporation for
National Research Initiatives (CNRI) and the leadership
of Cerf, then with CNRI.
In 1992, yet another reorganization took place. In
1992, the Internet Activities Board was re-organized and
re-named the Internet Architecture Board operating under
the auspices of the Internet Society. A more "peer"
relationship was defined between the new IAB and IESG,
with the IETF and IESG taking a larger responsibility for
the approval of standards. Ultimately, a cooperative and
mutually supportive relationship was formed between the
IAB, IETF, and Internet Society, with the Internet
Society taking on as a goal the provision of service and
other measures which would facilitate the work of the
IETF.
The recent development and widespread deployment of
the World Wide Web has brought with it a new community,
as many of the people working on the WWW have not thought
of themselves as primarily network researchers and
developers. A new coordination organization was formed,
the World Wide Web Consortium (W3C). Initially led from
MIT's Laboratory for Computer Science by Tim Berners-Lee
(the inventor of the WWW) and Al Vezza, W3C has taken on
the responsibility for evolving the various protocols and
standards associated with the Web.
Thus, through the over two decades of Internet
activity, we have seen a steady evolution of
organizational structures designed to support and
facilitate an ever-increasing community working
collaboratively on Internet issues.
Commercialization of the Technology
Commercialization of the Internet involved not only
the development of competitive, private network services,
but also the development of commercial products
implementing the Internet technology. In the early 1980s,
dozens of vendors were incorporating TCP/IP into their
products because they saw buyers for that approach to
networking. Unfortunately they lacked both real
information about how the technology was supposed to work
and how the customers planned on using this approach to
networking. Many saw it as a nuisance add-on that had to
be glued on to their own proprietary networking
solutions: SNA, DECNet, Netware, NetBios. The DoD had
mandated the use of TCP/IP in many of its purchases but
gave little help to the vendors regarding how to build
useful TCP/IP products.
In 1985, recognizing this lack of information
availability and appropriate training, Dan Lynch in
cooperation with the IAB arranged to hold a three day
workshop for ALL vendors to come learn about how TCP/IP
worked and what it still could not do well. The speakers
came mostly from the DARPA research community who had
both developed these protocols and used them in day to
day work. About 250 vendor personnel came to listen to 50
inventors and experimenters. The results were surprises
on both sides: the vendors were amazed to find that the
inventors were so open about the way things worked (and
what still did not work) and the inventors were pleased
to listen to new problems they had not considered, but
were being discovered by the vendors in the field. Thus a
two way discussion was formed that has lasted for over a
decade.
After two years of conferences, tutorials, design
meetings and workshops, a special event was organized
that invited those vendors whose products ran TCP/IP well
enough to come together in one room for three days to
show off how well they all worked together and also ran
over the Internet. In September of 1988 the first Interop
trade show was born. 50 companies made the cut. 5,000
engineers from potential customer organizations came to
see if it all did work as was promised. It did. Why?
Because the vendors worked extremely hard to ensure that
everyone's products interoperated with all of the other
products - even with those of their competitors. The
Interop trade show has grown immensely since then and
today it is held in 7 locations around the world each
year to an audience of over 250,000 people who come to
learn which products work with each other in a seamless
manner, learn about the latest products, and discuss the
latest technology.
In parallel with the commercialization efforts that
were highlighted by the Interop activities, the vendors
began to attend the IETF meetings that were held 3 or 4
times a year to discuss new ideas for extensions of the
TCP/IP protocol suite. Starting with a few hundred
attendees mostly from academia and paid for by the
government, these meetings now often exceeds a thousand
attendees, mostly from the vendor community and paid for
by the attendees themselves. This self-selected group
evolves the TCP/IP suite in a mutually cooperative
manner. The reason it is so useful is that it is
comprised of all stakeholders: researchers, end users and
vendors.
Network management provides an example of the
interplay between the research and commercial
communities. In the beginning of the Internet, the
emphasis was on defining and implementing protocols that
achieved interoperation. As the network grew larger, it
became clear that the sometime ad hoc procedures used to
manage the network would not scale. Manual configuration
of tables was replaced by distributed automated
algorithms, and better tools were devised to isolate
faults. In 1987 it became clear that a protocol was
needed that would permit the elements of the network,
such as the routers, to be remotely managed in a uniform
way. Several protocols for this purpose were proposed,
including Simple Network Management Protocol or SNMP
(designed, as its name would suggest, for simplicity, and
derived from an earlier proposal called SGMP) , HEMS (a
more complex design from the research community) and CMIP
(from the OSI community). A series of meeting led to the
decisions that HEMS would be withdrawn as a candidate for
standardization, in order to help resolve the contention,
but that work on both SNMP and CMIP would go forward,
with the idea that the SNMP could be a more near-term
solution and CMIP a longer-term approach. The market
could choose the one it found more suitable. SNMP is now
used almost universally for network based management.
In the last few years, we have seen a new phase of
commercialization. Originally, commercial efforts mainly
comprised vendors providing the basic networking
products, and service providers offering the connectivity
and basic Internet services. The Internet has now become
almost a "commodity" service, and much of the latest
attention has been on the use of this global information
infrastructure for support of other commercial services.
This has been tremendously accelerated by the widespread
and rapid adoption of browsers and the World Wide Web
technology, allowing users easy access to information
linked throughout the globe. Products are available to
facilitate the provisioning of that information and many
of the latest developments in technology have been aimed
at providing increasingly sophisticated information
services on top of the basic Internet data
communications.
History of the Future
On October 24, 1995, the FNC unanimously passed a
resolution
defining the term Internet. This definition was developed
in consultation with members of the internet and
intellectual property rights communities.
RESOLUTION: The Federal Networking Council
(FNC) agrees that the following language reflects our
definition of the term "Internet". "Internet" refers to
the global information system that -- (i) is logically
linked together by a globally unique address space based
on the Internet Protocol (IP) or its subsequent
extensions/follow-ons; (ii) is able to support
communications using the Transmission Control
Protocol/Internet Protocol (TCP/IP) suite or its
subsequent extensions/follow-ons, and/or other
IP-compatible protocols; and (iii) provides, uses
or makes accessible, either publicly or privately, high
level services layered on the communications and related
infrastructure described herein.
The Internet has changed much in the two decades since
it came into existence. It was conceived in the era of
time-sharing, but has survived into the era of personal
computers, client-server and peer-to-peer computing, and
the network computer. It was designed before LANs
existed, but has accommodated that new network
technology, as well as the more recent ATM and frame
switched services. It was envisioned as supporting a
range of functions from file sharing and remote login to
resource sharing and collaboration, and has spawned
electronic mail and more recently the World Wide Web. But
most important, it started as the creation of a small
band of dedicated researchers, and has grown to be a
commercial success with billions of dollars of annual
investment.
One should not conclude that the Internet has now
finished changing. The Internet, although a network in
name and geography, is a creature of the computer, not
the traditional network of the telephone or television
industry. It will, indeed it must, continue to change and
evolve at the speed of the computer industry if it is to
remain relevant. It is now changing to provide such new
services as real time transport, in order to support, for
example, audio and video streams. The availability of
pervasive networking (i.e., the Internet) along with
powerful affordable computing and communications in
portable form (i.e., laptop computers, two-way pagers,
PDAs, cellular phones), is making possible a new paradigm
of nomadic computing and communications.
This evolution will bring us new applications -
Internet telephone and, slightly further out, Internet
television. It is evolving to permit more sophisticated
forms of pricing and cost recovery, a perhaps painful
requirement in this commercial world. It is changing to
accommodate yet another generation of underlying network
technologies with different characteristics and
requirements, from broadband residential access to
satellites. New modes of access and new forms of service
will spawn new applications, which in turn will drive
further evolution of the net itself.
The most pressing question for the future of the
Internet is not how the technology will change, but how
the process of change and evolution itself will be
managed. As this paper describes, the architecture of the
Internet has always been driven by a core group of
designers, but the form of that group has changed as the
number of interested parties has grown. With the success
of the Internet has come a proliferation of stakeholders
- stakeholders now with an economic as well as an
intellectual investment in the network. We now see, in
the debates over control of the domain name space and the
form of the next generation IP addresses, a struggle to
find the next social structure that will guide the
Internet in the future. The form of that structure will
be harder to find, given the large number of concerned
stake-holders. At the same time, the industry struggles
to find the economic rationale for the large investment
needed for the future growth, for example to upgrade
residential access to a more suitable technology. If the
Internet stumbles, it will not be because we lack for
technology, vision, or motivation. It will be because we
cannot set a direction and march collectively into the
future.
Timeline
Footnotes
1 Perhaps this is
an exaggeration based on the lead author's residence in
Silicon Valley.
2 On a recent trip to
a Tokyo bookstore, one of the authors counted 14 English
language magazines devoted to the Internet.
3 An abbreviated version
of this article appears in the 50th anniversary issue of
the CACM, Feb. 97. The authors would like to
express their appreciation to Andy Rosenbloom, CACM
Senior Editor, for both instigating the writing of this
article and his invaluable assistance in editing both
this and the abbreviated version.
4 The Advanced Research
Projects Agency (ARPA) changed its name to Defense
Advanced Research Projects Agency (DARPA) in 1971, then
back to ARPA in 1993, and back to DARPA in 1996. We refer
throughout to DARPA, the current name.
5 It was from the RAND
study that the false rumor started claiming that the
ARPANET was somehow related to building a network
resistant to nuclear war. This was never true of the
ARPANET, only the unrelated RAND study on secure voice
considered nuclear war. However, the later work on
Internetting did emphasize robustness and survivability,
including the capability to withstand losses of large
portions of the underlying networks.
6 Including amongst others
Vint Cerf, Steve Crocker, and Jon Postel. Joining them
later were David Crocker who was to play an important
role in documentation of electronic mail protocols, and
Robert Braden, who developed the first NCP and then TCP
for IBM mainframes and also was to play a long term role
in the ICCB and IAB.
7 This was subsequently
published as V. G. Cerf and R. E. Kahn, "A
protocol for packet network interconnection" IEEE
Trans. Comm. Tech., vol. COM-22, V 5, pp. 627-641,
May 1974.
8 The desirability of
email interchange, however, led to one of the first
"Internet books": !%@:: A Directory of Electronic Mail
Addressing and Networks, by Frey and Adams, on email
address translation and forwarding.
9 Originally named
Federal Research Internet Coordinating Committee, FRICC.
The FRICC was originally formed to coordinate U.S.
research network activities in support of the
international coordination provided by the CCIRN.
10 The
decommisioning of the ARPANET was commemorated on its
20th anniversary by a UCLA symposium in 1989.
References
P. Baran, "On Distributed
Communications Networks", IEEE Trans. Comm.
Systems, March 1964.
V. G. Cerf and R. E. Kahn, "A
protocol for packet network interconnection", IEEE
Trans. Comm. Tech., vol. COM-22, V 5, pp. 627-641,
May 1974.
S. Crocker, RFC001 Host
software, Apr-07-1969.
R. Kahn, Communications Principles
for Operating Systems. Internal BBN memorandum, Jan.
1972.
Proceedings of the IEEE,
Special Issue on Packet Communication Networks, Volume
66, No. 11, November, 1978. (Guest editor: Robert Kahn,
associate guest editors: Keith Uncapher and Harry van
Trees)
L. Kleinrock, "Information Flow in
Large Communication Nets", RLE Quarterly Progress Report,
July 1961.
L. Kleinrock, Communication Nets:
Stochastic Message Flow and Delay, Mcgraw-Hill (New
York), 1964.
L. Kleinrock, Queueing Systems:
Vol II, Computer Applications, John Wiley and Sons
(New York), 1976
J.C.R. Licklider & W. Clark,
"On-Line Man Computer Communication", August 1962.
L. Roberts & T. Merrill, "Toward
a Cooperative Network of Time-Shared Computers", Fall
AFIPS Conf., Oct. 1966.
L. Roberts, "Multiple Computer
Networks and Intercomputer Communication", ACM Gatlinburg
Conf., October 1967.
Authors
Barry
M. Leiner is an independent consultant in networking
and distributed systems.
Vinton
G. Cerf is Senior Vice President, Internet
Architecture and Engineering, at MCI
Communications Corp.
David
D. Clark is Senior Research Scientist at the
MIT Laboratory for
Computer Science
Robert
E. Kahn is President of the Corporation
for National Research Initiatives
Leonard
Kleinrock is Professor of computer science at the
University of California, Los Angeles
Daniel
C. Lynch is Chairman of CyberCash
Inc. and founder of the Interop networking trade show
and conferences
Jon
Postel is Director of the Computer Networks Division
of the Information Sciences
Institute of the University of Southern
California
Lawrence
G. Roberts is President of ATM Systems Division of
Connectware
Inc.
Stephen
Wolff is with Cisco
Systems, Inc.
GTF
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