Transcript History of Communication

Genghis Khan’s Empire at His Death at 1227
Hui Zhang, Fall 2012
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Early Communication over Long
Distance
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Between human beings
Letter and messenger
- Information carried by physical objects
- Speed limited by transportation means: horse, bird,
train, car
- Bandwidth? distance? security?
Fire
- Early optical communication
- Speed of light
- Bandwidth? distance? security?
Hui Zhang, Fall 2012
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Transcontinental Railroad: 1869
Hui Zhang, Fall 2012
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Telegraph: Communication Using
Electrons
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Between human beings
Major milestones:
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1827: Ohm’s Law
1837: “workable” telegraph invented by Samuel Morse
1838: demonstration over 10 miles at 10 w.p.m
1844: Capitol Hill to Baltimore
1851: Western Union founded
1868: transatlantic cable laid
1985: last telegraph circuit closed down
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Telegraph Engineering
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Technical issues
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How to encode information?
How to feed/input information to the system?
How to output information?
How to improve the distance?
How to improve the speed?
How to improve the simultaneous # of telegraphs?
Common issues faced by all telecommunication
systems
Hui Zhang, Fall 2012
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Telephony Milestones
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1876: Alaxendar Bell invented telephone
1878: Public switches installed at New Haven and San
Francisco, public switched telephone network is born
• People can talk without being on the same wire !
Without Switch
Hui Zhang, Fall 2012
With Switch
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Telephony Milestones
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1878: First telephone directory; white house line
1879 Patent settlement between West Union and Bell
1881: Insulated, balanced twisted pair as local loop
1885: AT&T formed
1892: First automatic commercial telephone switch
1903: 3 million telephones in U.S.
1915: First transcontinental telephone line
1927: First commercial transatlantic commercial service
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Telephony Milestones
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1937: Multiplexing introduced for inter-city calls
Without Multiplexing
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With Multiplexing
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Telephony Technology Milestones
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Encoding technology
- 1939: Pulse Code Modulation (PCM) invented
Basic technology
- 1948: Transistor invented by Bell scientists
Automation
- 1951: Direct dialing for long-distance demonstrated
Transmission technology
- 1963: Digital transmission introduced
- 1983 First fiber-optic cable in ATT long distance network
Switching technology
- 1965 1ESS central office switch introduced
• Stored Program Control (computerized)
- 1976 4ESS: first digital electronic switch
- Hui
1999
4ESS switch installed in ATT network
Zhang, FallLast
2012
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End Device Evolution
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Switch Evolution
1ESS
4 ESS
Early Phone
Switch Center
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Cisco Router
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History of the Internet
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70’s: started as a research project, 56 kbps, < 100
computers
80-83: ARPANET and MILNET split
85-86: NSF builds NSFNET as backbone, links 6
Supercomputer centers, 1.5 Mbps, 10,000 computers
87-90: link regional networks, NSI (NASA), ESNet(DOE),
DARTnet, TWBNet (DARPA), 100,000 computers
90-92: NSFNET moves to 45 Mbps, 16 mid-level networks
94: NSF backbone dismantled, multiple private backbones
Today: backbones run at 10 Gbps, hundreds of millions
devices around the world
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Topology of ARPANet
56 Kbps
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Devices of ARPANet
Backplane
PDP-10
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IMP
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End Device Evolution
Computer
Without
Network
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Today’s Internet End Devices
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Network Evolution
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Commercial Internet after 1994
Joe's Company
Campus Network
Berkeley
Stanford
Regional ISP
Bartnet
Xerox Parc
SprintNet
America On Line
UUnet
NSF Network
IBM
NSF Network
Modem
AT&T
IBM
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A Taxonomy of Communication
Networks
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Communication networks can be classified based on
the way in which the nodes exchange information:
Communication
Network
Switched
Communication
Network
Circuit-Switched
Communication
Network
Broadcast
Communication
Network
Packet-Switched
Communication
Network
Datagram
Network
Hui Zhang, Fall 2012
Virtual Circuit Network
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What is a Communication Network?
(from end-system point of view)
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Network offers a service: move information
- Bird, fire, messenger, truck, telegraph, telephone, Internet …
- Another example, transportation service: move objects
• Horse, train, truck, airplane ...
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What distinguish different types of networks?
- The services they provide
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What distinguish the services?
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Latency
Bandwidth
Loss rate
Number of end systems
Service interface
Other details
• Reliability, unicast vs. multicast, real-time, message vs. byte ...
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What is a Communication Network?
Infrastructure Centric View
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Electrons and photons as communication medium
Links: fiber, copper, satellite, …
Switches: electronic/optic, crossbar/Banyan
Protocols: TCP/IP, ATM, MPLS, SONET, Ethernet, X.25, FrameRelay,
AppleTalk, IPX, SNA
Functionalities: routing, error control, flow control, congestion control,
Quality of Service (QoS)
Applications: telephony, FTP, WEB, X windows, Search, Youtube,
Facebook ...
Hui Zhang, Fall 2012
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Summary
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Communication long before computer
Evolutions of modern communication and computer
intertwined
Component centric view
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End devices (telephone, computer, smartTV)
Switch (analog vs. digital, circuit vs. packet)
Transmission (copper, fiber, wireless)
Protocol (TCP/IP, Ethernet, ATM, WiFi)
Service centric view
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Service interface (bytestream vs. datagram, SOAP vs. REST)
Performance: reliability, latency, throughput
Security
Point to point vs. multicast vs. broadcast
Hui Zhang, Fall 2012
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Key Drivers for Computer Networks
Evolution
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Computers and other smart devices
Routers/switches
Transmission technologies
- vDSL, DWDM, WiFi, WiMax, 4G
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Applications
- telnet, FTP, Web, e-commerce, social, search, voice, video,
gaming, etc …
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Software
- Distributed control software for the infrastructure
(switching/routing protocols, DNS, CDN)
- End device software
- Server software
- Application software (device, cloud)
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Other Key Aspects of The Most
Important Global Infrastructure
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Dependability, security, and manageability
Industry structure and regulation
Global politics
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