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 handed off 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 big file #9#8#7 #6#5#4 #3#2#1