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Hui Zhang, Fall 2012 1 Genghis Khans Empire at His Death at 1227
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Hui Zhang, Fall 2012 2 Early Communication over Long Distance 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?
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Hui Zhang, Fall 2012 3 Transcontinental Railroad: 1869
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Hui Zhang, Fall 2012 4 Telegraph: Communication Using Electrons Between human beings Major milestones: -1827: Ohms 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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Hui Zhang, Fall 2012 5 Telegraph Engineering Technical issues -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
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Hui Zhang, Fall 2012 6 Telephony Milestones 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 SwitchWith Switch
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Hui Zhang, Fall 2012 7 Telephony Milestones 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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Hui Zhang, Fall 2012 8 Telephony Milestones 1937: Multiplexing introduced for inter-city calls Without Multiplexing With Multiplexing
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Hui Zhang, Fall 2012 9 Telephony Technology Milestones 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 -1999 Last 4ESS switch installed in ATT network
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Hui Zhang, Fall 2012 10 End Device Evolution
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Hui Zhang, Fall 2012 11 Switch Evolution Early Phone Switch Center 1ESS 4 ESS Cisco Router
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Hui Zhang, Fall 2012 12 History of the Internet 70s: 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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Hui Zhang, Fall 2012 13 Topology of ARPANet 56 Kbps
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Hui Zhang, Fall 2012 14 Devices of ARPANet PDP-10 Backplane IMP
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Hui Zhang, Fall 2012 15 End Device Evolution Computer Without Network
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Hui Zhang, Fall 2012 16 Todays Internet End Devices
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Hui Zhang, Fall 2012 17 Network Evolution
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Hui Zhang, Fall 2012 18 Commercial Internet after 1994 NSF Network Regional ISP America On Line IBM Bartnet Campus Network Joe's Company Stanford Xerox Parc Berkeley NSF Network AT&T UUnet SprintNet Modem IBM
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Hui Zhang, Fall 2012 19 Communication networks can be classified based on the way in which the nodes exchange information: A Taxonomy of Communication Networks Communication Network Switched Communication Network Broadcast Communication Network Circuit-Switched Communication Network Packet-Switched Communication Network Datagram Network Virtual Circuit Network
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Hui Zhang, Fall 2012 20 What is a Communication Network? (from end-system point of view) Network offers a service: move information -Bird, fire, messenger, truck, telegraph, telephone, Internet … -Another example, transportation service: move objects Horse, train, truck, airplane... What distinguish different types of networks? -The services they provide What distinguish the services? -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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Hui Zhang, Fall 2012 21 What is a Communication Network? Infrastructure Centric View 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...
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Hui Zhang, Fall 2012 22 Summary Communication long before computer Evolutions of modern communication and computer intertwined Component centric view -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 -Service interface (bytestream vs. datagram, SOAP vs. REST) -Performance: reliability, latency, throughput -Security -Point to point vs. multicast vs. broadcast
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Hui Zhang, Fall 2012 23 Key Drivers for Computer Networks Evolution Computers and other smart devices Routers/switches Transmission technologies -vDSL, DWDM, WiFi, WiMax, 4G Applications -telnet, FTP, Web, e-commerce, social, search, voice, video, gaming, etc … 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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Hui Zhang, Fall 2012 24 Other Key Aspects of The Most Important Global Infrastructure Dependability, security, and manageability Industry structure and regulation Global politics
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