7/12: Ch. 6 Telecommunications - PowerPoint PPT Presentation

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7/12: Ch. 6 Telecommunications
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7/12: Ch. 6 Telecommunications

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  1. 7/12: Ch. 6 Telecommunications • Business Value of Telecommunications • Trends • Industry • Technology • Application • Internet applications • Network models • WANs, LANs, Internetworks, Intranets, Extranets, Client/Server, Interorganizational

  2. Business Value • How businesses use telecommunications • enterprise collaboration • electronic commerce • internal business • Business Value of Telecommunications • overcoming barriers: geographical, time, cost, structural

  3. Trends • Industry • increased number of suppliers • deregulation act create more suppliers • Technology • Open systems increase connectivity • Digital overtakes analog • Wireless • Application • applying telecommunications to every aspect of busines

  4. Internet Applications • origins: ARPANET – Defense Dept. project • WWW – Tim Berners-Lee at CERN (Switz.) • Email • Usenet (newsgroups) • IRC (chat rooms, AIM) • FTP • Telnet

  5. Network Models • basic model: • terminal – processor – channel – processor – terminal • includes software at most points

  6. Network Models • WAN – Wide Area Network • LAN – Local Area Network • network servers, shared peripherals, etc. • Internetworks – Networked LANs • using processors: switches, routers, hubs, gateways • Intranets & Extranets – WWW for internal & external use -- VPNs • Client/Server – applications reside on server • client programs reside on terminals (PCs)

  7. Part 2: Alternatives • Media choices • Twisted pair, coaxial cable, fiber optics, microwaves, satellites, cellular phone systems, wireless LANs • Processors • Modems, multiplexers, internetwork processors • Software – common functions • Network Topologies • Star, bus, ring • Architecture & Protocols • TCP/IP, OSI

  8. Media Choices • Twisted Pair Wire • telephone wire • Coaxial Cable • cable TV • Fiber Optics • glass fibers use light to transmit data images courtesy of mag-nify.educ.monash.edu.au,www.mars-cam.com, 3Com.com

  9. Media Choices • Terrestrial Microwaves • line-of-sight up to 30 miles apart • Communication Satellites • DirectPC, DirectTV • Cellular Phone Systems • Wireless LANs • radio, infrared images courtesy of mitsubishi.com

  10. Processor Choices • Modems • Analog modems (telephone) • ISDN, Cable, DSL modems • Multiplexers • allow multiple users on same channel • FDM, TDM, STDM • Internetwork Processors • switches, hubs - complete connections • routers, gateways – interfaces for networks image courtesy of 3Com

  11. Software • Access control • autodialers, log-ins, etc. • Transmission control • error checking (parity checking) • transmission of data, etc. (often file transfer) • Network management • prioritizes traffic on network • prevents (or deals with) data collisions, etc. • Security management • includes encryption, access validation

  12. Network Topologies • nodes, hubs, backbones, servers • Star • central server control • Bus • like a highway • Ring • control gets handedoff from node to node

  13. Architecture & Protocols • circuit-switched networks • telephone conversation: whole circuit reserved • packet-switched networks • shared passages, packets of information being sent • Internet: packet-switched (ex. TCP)

  14. Internet Protocol (IP) • address: 4 separate 3-digit numbers separated by periods • looking up IPs at Internic.net • URLs are used to look up IP addresses at Domain Name Servers (DNS) 165.134. 1 . 25 209.145.150. 10

  15. Transmission Control Protocol (TCP) • breaks message into manageable chunks and sends them separately • like packing up a house’s contents to move #1 #2 #3 big file #4 #5 #6 #7 #8 #9