Genghis Khan ’ s Empire at His Death at 1227

1. Genghis Khan’s Empire at His Death at 1227

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?

3. Transcontinental Railroad: 1869

4. Telegraph: Communication Using Electrons • Between human beings • Major milestones: • 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

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

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 Switch With Switch

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

8. Telephony Milestones • 1937: Multiplexing introduced for inter-city calls With Multiplexing Without Multiplexing

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

10. End Device Evolution

11. Switch Evolution 1ESS 4 ESS Early Phone Switch Center Cisco Router

12. History of the Internet • 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

13. Topology of ARPANet 56 Kbps

14. Devices of ARPANet Backplane PDP-10 IMP

15. End Device Evolution Computer Without Network

16. Today’s Internet End Devices

17. Network Evolution

18. Commercial Internet after 1994 Joe's Company Berkeley Stanford Regional ISP Campus Network Bartnet Xerox Parc SprintNet America On Line UUnet NSF Network IBM NSF Network Modem AT&T IBM

19. A Taxonomy of Communication Networks • Communication networks can be classified based on the way in which the nodes exchange information: Communication Network SwitchedCommunication Network BroadcastCommunication Network Packet-SwitchedCommunication Network Circuit-SwitchedCommunication Network Virtual Circuit Network Datagram Network

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 ...

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 ...

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

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)

24. Other Key Aspects of The Most Important Global Infrastructure • Dependability, security, and manageability • Industry structure and regulation • Global politics