Transcript History of the Internet Part 1

History of the Internet
Part 1
How the environment came to be.
1962 – J.C.R. Licklider
• Idea of global network proposed.
– He envisioned a globally interconnected set of
computers through which everyone could
quickly access data and programs from any site.
• As head of DARPA (Defense Advanced
Research Projects Agency) and by
convincing his successors, was able to push
forward his ideas.
1961-1964 : Leonard Kleinrock
• 1961 published the first paper on packet
switching theory.
• 1964 Published the first book on the
subject.
• Before the idea of using packets to
communicate, circuit communication was
the only way.
Packets vs. Circuits
• Circuit communication functions by having
a set path going from entity A to entity B
and back again.
– Phones used these type of communication for a
long time.
– No one else can use any part of the path while
its in use.
– Sends the whole thing.
Packets vs. Circuits
• Packet communication functions by
breaking up the communication into smaller
chunks and letting each of those chunks find
their own way.
– Doesn’t tie down the entire path while
communication is going on.
– Issues of how packets can efficiently find their
way, assembling them back in the proper order,
and lost packets.
The First WAN - 1965
• Kleinrock convinced a Lawrence G.
Roberts (one of the DARPA guys) of the
feasibility of packet communication.
• Thomas Merrill and Roberts connected the
TX-2 computer in Mass. with the Q-32
computer in Calif. using a telephone line.
– Key discovery: Circuit communication bad,
packets good.
Putting all the Pieces Together
• 1966 : Roberts goes to DARPA (sorta like Mr.
Smith goes to Washington) to develop the
computer network concept further.
– 1967 : Publishes plans for the ARPANET.
• At a conference discovers two other groups had
been working on packet switching as well: NPL
and RAND.
– Helps to refine his ideas for the ARPANET
– 50 kbps line speed proposed
Building of the ARPANET -1968
• Frank Heart at Bolt Beranek and Newmann
headed a group that was funded to build the
hardware (called: Interface Message Processors)
required for packet switching to work.
• Roberts and others focused on the overall
architectural design, network topology, and
economics.
• A system to measure the network was prepared by
Kleinrock’s team at UCLA.
A Working Model
• 1969 : ARPANET comes into being.
– A two node WAN using packet-switching.
– One computer was at UCLA, the other at
Stanford Research Institute (SRI).
• At SRI Doug Engelbart had developed
NLS, an early hypertext system.
– Key because HTML is basically a hypertext
system.
A Working Model
• SRI supported the Network Information
Center led by Elizabeth (Jake) Feinler.
– Maintained tables of host name to address
mapping.
• One month after the computers were
connected the first host-to-host message
was sent.
A Working Model
• After UCLA and SRI were successfully
connected together two additional nodes
were added at UC Santa Barbara and the
University of Utah.
– Incorporated Visualization projects dealing with
the display of 3-D material over the net.
• 1969 : 4 Computers on the ARPANET
– Work focused on both the network itself and
how to utilize the network.
Building Applications
• 1970 : The Network Working Group under S.
Crocker finished the initial ARPANET Host-toHost protocol, called the Network Control
Protocol (NCP).
• 1972 : Ray Tomlinson at BBN creates Email,
causing a growth in people-to-people
communication.
– Roberts expanded the basic Email program which
functionality such as list, file, forward, and reply.
Upgrading the Network Protocol
• NCP could not address networks and machines
further downstream than a destination IMP
(Interface Message Processor) on the ARPANET.
• NCP relied on ARPANET to provide end-to-end
reliability.
– i.e. NCP assumed there would be no errors or lost
packets.
• Thus, the need for a new version of the NCP
protocol for an open-architecture network
environment.
Upgrading the Network Protocol
• 1973 : Kahn and Vint Cerf develop a new
protocol which comes to be named
Transmission Control Protocol/Internet
Protocol (TCP/IP).
• Where NCP was more like a device driver,
TCP/IP is more like an actual
communication’s protocol.
The Four Ground Rules
1. 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.
2. Communications would be on a best effort basis.
3. Black boxes (Gateways and Routers) would be
used to connect the networks.
4. No global control at the operations level.
Key Problems to Solve
• Dealing with packet loss.
• Multiple packets enroute.
• Proper packet forwarding by gateways and
routers.
• Error checking for the packets.
• Global addressing.
• Flow controls.
• Interfacing the various operating systems.
Initial Solutions
• Communication would consist of a very long
stream of bytes.
– The position of any byte in the stream would be used to
identify it.
• Flow control would be done by using sliding
windows and acknowledgements.
• Not expecting the massive growth of LAN’s, the
32 bit IP address scheme was used.
– Assumes only 256 individual networks.
Side Notes
• Packet recover is not always a good thing.
• Splitting of TCP and IP.
– TCP : No packet left behind.
– UDP : Every packet for himself or herself.
Taking Form
• 1973 : To allow all the different WANs to
communicate together TCP/IP and the host
naming scheme is developed. The Internet
that we know starts to form.
– Robert Kahn and Dr. Vinton Cerf
• 1980’s : Wide growth of TCP/IP, new
applications such as Telnet and FTP are
created.
(Abbr.) Chronology
• 1982 : 235 computers connected to the ARPANET.
• 1984 : NSF (National Science Foundation) funded
the networking of Universities together using the
new technology.
– ARPTANET becomes just one of a number of smaller
networks connected together.
• 1989 : Tim Berners-Lee comes up with initial idea
for a hypertext distribution system.
(Abbr.) Chronology
• 1990 : 300,000 computers on 3,000 separate
networks connected together.
• 1991 : Berners-Lee develops his idea into
pages of information connected together via
links, he calls it the World Wide Web.
– Pages could be accessed over computer
networks using the IP address combined with
the name of the page. -> URL (Uniform
Resource Locator)
(Abbr.) Chronology
• 1993 : The prototype of today’s Web
Browsers, Mosaic, is developed.