Transcript Internet

Internet History
CS 4244: Internet Programming
Dr. Eli Tilevich
US Science and Technology Policy in
the Second Half of the 20th Century
• Five decades of history:
– The lessons of the “Manhattan Project.”
– The 50’s: Complacency.
– October 4, 1957.
• NASA 1958
• (D)ARPA 1958
Major Themes of Technological
Progress
• The 60’s: Networking (packet switching)
• The 70’s: UNIX (Berkeley and AT&T)
• The 80’s PC (IBM, Apple, Microsoft)
– 1979 3Com
– 1979 Novel
– 1981 SUN
– 1984 CISCO
Chapter 1
Introduction
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Thanks and enjoy! JFK/KWR
All material copyright 1996-2005
J.F Kurose and K.W. Ross, All Rights Reserved
Computer Networking:
A Top Down Approach
Featuring the Internet,
3rd edition.
Jim Kurose, Keith
Ross
Addison-Wesley, July
2004.
Internet History
1961-1972: Early packet-switching principles
• 1961: Kleinrock - queueing
• 1972:
theory shows effectiveness of
– ARPAnet public demonstration
packet-switching
– NCP (Network Control Protocol)
• 1964: Baran - packetfirst host-host protocol
switching in military nets
– first e-mail program
• 1967: ARPAnet conceived by
– ARPAnet has 15 nodes
Advanced Research Projects
Agency
• 1969: first ARPAnet node
operational
Internet History
1972-1980: Internetworking, new and proprietary
• 1970: ALOHAnet satellite nets
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network in Hawaii
1974: Cerf and Kahn architecture for
interconnecting networks
1976: Ethernet at Xerox
PARC
late70’s: proprietary
architectures: DECnet,
SNA, XNA
late 70’s: switching fixed
length packets (ATM
precursor)
1979: ARPAnet has 200
nodes
Cerf and Kahn’s internetworking
principles:
– minimalism, autonomy - no
internal changes required
to interconnect networks
– best effort service model
– stateless routers
– decentralized control
define today’s Internet
architecture
Internet History
1980-1990: new protocols, a proliferation of
networks
• 1983: deployment of
TCP/IP
• 1982: smtp e-mail
protocol defined
• 1983: DNS defined for
name-to-IP-address
translation
• 1985: ftp protocol defined
• 1988: TCP congestion
control
• new national networks:
Csnet, BITnet, NSFnet,
Minitel
• 100,000 hosts connected
to confederation of
networks
Internet History
1990, 2000’s: commercialization, the Web, new
apps
• Early 1990’s: ARPAnet
decommissioned
• 1991: NSF lifts restrictions on
commercial use of NSFnet
(decommissioned, 1995)
• early 1990s: Web
– hypertext [Bush 1945, Nelson
1960’s]
– HTML, HTTP: Berners-Lee
– 1994: Mosaic, later Netscape
– late 1990’s: commercialization
of the Web
Late 1990’s – 2000’s:
• more killer apps: instant
messaging, P2P file sharing
• network security to forefront
• est. 50 million host, 100
million+ users
• backbone links running at
Gbps
Internet From the Networking
Perspective
Overview
What’s the Internet: “nuts and bolts”
view
• millions of connected
computing devices:
hosts = end systems
• running network apps
• communication links
router
server
workstation
mobile
local ISP
– fiber, copper, radio, satellite
– transmission rate =
bandwidth
regional ISP
• routers: forward packets
(chunks of data)
company
network
“Cool” internet appliances
Web-enabled toaster +
weather forecaster
IP picture frame
http://www.ceiva.com/
World’s smallest web server
http://www-ccs.cs.umass.edu/~shri/iPic.html
Internet phones
What’s the Internet: “nuts and bolts”
view
• protocols control sending,
receiving of msgs
– e.g., TCP, IP, HTTP, FTP, PPP
• Internet: “network of
networks”
router
server
mobile
local ISP
– loosely hierarchical
– public Internet versus private
intranet
regional ISP
• Internet standards
– RFC: Request for comments
– IETF: Internet Engineering Task
Force
workstation
company
network
What’s the Internet: a service view
• communication
infrastructure enables
distributed applications:
– Web, email, games, ecommerce, file sharing
• communication
services provided to
apps:
– Connectionless
unreliable
– connection-oriented
reliable
A closer look at network structure:
• network edge:
applications and
hosts
• network core:
– routers
– network of networks
• access networks,
physical media:
communication links
The network edge:
• end systems (hosts):
– run application programs
– e.g. Web, email
– at “edge of network”
• client/server model
– client host requests, receives
service from always-on server
– e.g. Web browser/server; email
client/server
• peer-peer model:
– minimal (or no) use of
dedicated servers
– e.g. Gnutella, KaZaA, Skype
Network edge: connection-oriented
service
Goal: data transfer
TCP service [RFC 793]
between end systems
• reliable, in-order byte• handshaking: setup
stream data transfer
(prepare for) data transfer
– loss: acknowledgements and
retransmissions
ahead of time
– Hello, hello back human
• flow control:
protocol
– set up “state” in two
communicating hosts
• TCP - Transmission
Control Protocol
– Internet’s connectionoriented service
– sender won’t overwhelm
receiver
• congestion control:
– senders “slow down sending
rate” when network
congested