Telecommunications, Networks, and Wireless Computing

1. SESSION 8 Telecommunications, Networks, and Wireless Computing

2. TELECOMMUNICATIONS • Telecommunications: Communication of all types of information, including digital data, voice, fax, sound, and video from one location to another over some type of network • Network: A group of computers and associated peripheral devices connected by a communication channel of sharing information and other resources among users

3. RECEIVER Basic Communications Model SENDER MEDIUM

4. Types of Data • Text • Voice • Image • Video

5. The Corporate Telecommunications System Features of Contemporary Telecommunications Systems Three Major Developments Shaping Contemporary Systems • Client/server computing • Packet switching • TCP/IP and other communications standards

6. The Corporate Telecommunications System A corporate telecommunications system Figure 8-1

7. The Corporate Telecommunications System Features of Contemporary Telecommunications Systems Client/Server Computing • Powerful personal computers connect to network with one or more server computers • Has extended networking to parts of business that could not be served by centralized architecture • Processing load balanced over many smaller machines

8. The Corporate Telecommunications System Features of Contemporary Telecommunications Systems Packet Switching • Messages broken into “packets” before transmission • Packets include destination and error-checking information • Packets travel independently using routers; reassembled into original message at destination

9. The Corporate Telecommunications System Packet-switched networks and packet communications Figure 8-2

10. Packet Switching • Packet switching breaks transmissions into packets • When a packet arrives at a switch, the switch must decide where to send the packet next D E Switch Switch A Trunk Line C B

11. The Corporate Telecommunications System Features of Contemporary Telecommunications Systems TCP/IP Transmission Control Protocol/Internet Protocol • Open suite of protocols for connectivity developed in 1970s • Provides standards for breaking messages into packets, routing them to destination addresses, and reassembling them at end • Allows for communication regardless of hardware/software

12. The Corporate Telecommunications System Features of Contemporary Telecommunications Systems TCP/IP: Four-Layer Reference Model • Application layer: Communication between applications and other layers • Transport layer: Acknowledging and sequencing packets to/from application • Internet layer: Addressing, routing, packaging data packets • Network interface layer: Placing packets on and receiving them from network medium

13. The Corporate Telecommunications System The Transmission Control Protocol/Internet Protocol (TCP/IP) reference model Figure 8-3

14. Communication Media/Channels • Guided Media: • Twisted Pair • Coaxial Cable • Optical Fiber • Unguided Media: • Microwave • Satellite • Broadcast Radio

15. Twisted Pair Coaxial Cable Optical Fiber Guided Media

16. Analog and digital signals • Analogue signal: a continuous wave • Digital: a discrete set of on (1) and off (0) electronic bursts rather than a continuous wave. +1 0 1 1 0 0

17. Digital Digital Analog Modem Modem Medium: phone network

18. Unguided Media: Microwave • Microwave- “Line of sight” media: • antennas need to see each other

19. Unguided Media: Satellite

21. The Corporate Telecommunications System Transmission Media Transmission Speed • Bps: Bits per second • Baud rate: Rate of signal changes • One signal change = cycle • Transmission capacity is function of frequency • Bandwidth: Range of frequencies accommodated on a particular channel

22. The Corporate Telecommunications System Transmission Media Transmission Speed

23. Computer Networks • By geographic span • Local Area Network (LAN) • Wide Area Network (WAN) • By topology (physical) • Star • Bus • Ring • Mesh • By architecture (logical) • Peer to peer versus client-server • Centralized versus distributed versus hybrid

24. Network Topology: STAR

25. Network Topology: Bus

26. Network Topology: Ring

27. Communications Networks Network topologies Figure 8-8

28. COMMUNICATIONS NETWORKS Local Area Networks • Encompass a limited distance • Require its own communication channels • Support high volumes of data and functions requiring high transmission speed • Gateway, router, Network Operating System (NOS)

29. COMMUNICATIONS NETWORKS A Local Area Network (LAN)

30. COMMUNICATIONS NETWORKS Wide Area Networks (WANs) • Span large geographical distance • Consist of variety of switched and dedicated lines, satellite, and microwave technologies

31. Internet Architecture

34. Communications Networks Wireless Networks: Wi-Fi and Bluetooth • Use radio waves to connect stations • 802.11b: Current standard; 54 Mbps in 2.4 GHz range • Infrastructure mode: Wireless devices communicate with wired LAN via access points • Ad-hoc mode: Peer-to-peer mode; wireless devices communicate with each other directly

35. Communications Networks An 802.11 wireless LAN

36. Communications Networks Wireless Networks: Wi-Fi and Bluetooth • Hot spot: Geographic location in which an access point provides public Wi-Fi network service • Bluetooth: Standard for wireless personal area networks that can transmit up to 722 Kbps within 10-meter area

37. Case Analysis Is the World Falling for Wi-Fi? Textbook Page 280

38. Communications Networks Broadband Network Services and Technologies • Frame relay • Asynchronous transfer mode (ATM) • Integrated Services Digital Network (ISDN) • Digital subscriber line (DSL) • T1 line • Network convergence • VAN: Value Added Network

39. Electronic Business and Electronic Commerce Technologies Electronic Mail and Groupware • E-mail • Eliminates telephone tag and costly long-distance telephone charges • Groupware • Enables work groups at different locations to participate in discussion forums and work on shared documents and projects

40. Electronic Business and Electronic Commerce Technologies Voice Mail and Fax • Voice mail • Digitizes spoken message and transmits it over a network • Fax • Digitizes and transmits documents over telephone lines

41. Electronic Business and Electronic Commerce Technologies Teleconferencing, Dataconferencing, and Videoconferencing • Teleconferencing • Ability to confer with a group of people simultaneously • Data conferencing • Two or more users can edit and modify data files simultaneously • Videoconferencing • Participants are able to see each other over video screens

42. Electronic Business and Electronic Commerce Technologies Digital Information Services, Distance Learning, and E-Learning • Digital Information Services: • Online services providing general and business information, such as LexisNexis, AOL, Dow Jones News • Distance learning • Education or training delivered over a distance to individuals in one or more locations • E-learning • Instruction delivered online using the Internet or private networks

43. Electronic Business and Electronic Commerce Technologies Electronic Data Interchange • Computer-to-computer exchange between two organizations of standard transaction documents, such as invoices, purchase orders • Minimizes paper-handling and data input; lowers transaction costs • Transmits structured data with fields, unlike e-mail

44. Electronic Business and Electronic Commerce Technologies Electronic data interchange (EDI) Figure 8-10

45. Developing a Business-Driven Telecommunications Plan Implementation Issues: Seven Factors • Distance • Services • Points of access • Utilization • Cost • Security • Connectivity