Telecommunications, the Internet, & Wireless Technology

1. Telecommunications, the Internet, & Wireless Technology MIS 205 LECTURES Faculty: MzF

2. Trends in Telecommunications • New hardware devices; new alternatives for business & non-business communications (e.g., the RIM Blackberry) • Telecommunications deregulation encouraged competition • Dominance of Internet technologies in voice, data, & video communications • High-speed broadband connections to homes & businesses • Growth in wireless telephone & wireless computer networks • Growing scope of communication-intense products (e.g., Internet telephony, mobile commerce) ADM2372, M Benyoucef, Fall'08

3. Trends in Telecommunicationsimpact on business • Declining transaction costs • Declining agency costs • Increased agility • Higher quality management decisions • Declining geographical barriers • Declining time barriers (work 24/7) ADM2372, M Benyoucef, Fall'08

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9. Components of a Simple Network Network: 2 or more connected computers NOS (Network Operating System): routes & manages communications on the network & coordinates network resources NIC: Network Interface Card Switch: filters & forwards data to specified locations within a network Router: send packets of data though different networks ADM2372, M Benyoucef, Fall'08

10. Data Communicationswhat (1) • Data communication: the process of transferring data, information or commands between 2 computers or between a computer and a terminal • Data communication requires • Transmitter & receiver • Protocol: set of rules • Medium • Message Medium Transmitter Receiver Message Protocol Source: Davis & Benamati, Ecommerce basics, Addison Wesley, 2002, Page 36 ADM2372, M Benyoucef, Fall'08

11. Data Communicationswhat (2) • Transmitter/Receiver • Computer, terminal, hardware in general • e.g., PC, Cell phone, PDA, Kiosk, cash register, etc. • Medium • Wired (cable) • Twisted pair of wires (phone) • Coaxial cable (cable TV) • Fiber-optic cable • etc. • Wireless • Radio (laptop with a wireless card, Wireless Fidelity - Wi-Fi) • Satellite • Infrared (wireless keyboard) ADM2372, M Benyoucef, Fall'08

12. Data Communicationsfiber optic cables • Thin strands of clear glass fiber • Data is transformed into pulses of light and sent over the cable • trillions of bits per second • Faster, lighter, durable, expensive, hard to install • Harder to hack (harder to listen to pulses of light) • Often used as a backbone (i.e., to carry signals to distribution nodes) • Dense Wave Division Multiplexing (DWDM) • Next-generation optical network • Uses many colors (wavelengths) of light (up to 160)  even greater capacity ADM2372, M Benyoucef, Fall'08

13. Data CommunicationsTCP/IP (1) • Transmission Control Protocol / Internet Protocol (TCP/IP) • The communications protocol of the Internet • In order for any computer to use the Internet, it must be equipped with the software that enables this protocol • TCP/IP is based on “packet switching” - i.e., dividing messages into packets and sending each one individually ADM2372, M Benyoucef, Fall'08

14. Data CommunicationsTCP/IP (2) - packet switching Packet switching: Technology that breaks blocks of data into fixed bundles and routes them in the most economical way through any available channel. Packets are reassembled once they reach their destination ADM2372, M Benyoucef, Fall'08

15. Data CommunicationsTCP/IP (3) • IP (Internet Protocol) • Specifies the format of packets & addressing scheme • Addresses a packet and drops it in the system • TCP (Transmission Control Protocol) • Enables two hosts to establish a connection for a period of time to exchange data • Guarantees that packets are delivered in the same order in which they were sent ADM2372, M Benyoucef, Fall'08

16. Data Communicationsvoice over IP (1) • Uses IP (Internet protocol) to deliver voice in digital form • Based on “packet switching” (instead of “circuit switching” used in regular telephone communications) • Low cost • Some delay in transmission (compared to circuit switching)  low sound quality • If high bandwidth  better sound quality ADM2372, M Benyoucef, Fall'08

17. Data Communicationsvoice over IP (2) 3 2 4 1 5 ADM2372, M Benyoucef, Fall'08

18. Data Communicationsbandwidth (1) • Bandwidth • Measures the amount of data a medium can transmit in a given period of time • bps (bits per second) • Kbps, Mbps or Gbps • K (1000), M (1 million), G (1 billion) • Baseband: one line, one channel • most local communications • Broadband: one line, simultaneous channels • DSL (Digital Subscriber Line) • Bell • Cable • Rogers ADM2372, M Benyoucef, Fall'08

19. Data Communicationsmodem (1) • Analog signal • Continuous waveform • Voicecommunications • Digital signal • Discrete waveform • Two states: 0 and 1 • On-off electrical pulses • Data communications ADM2372, M Benyoucef, Fall'08

20. Data Communicationsmodem (2) • Modem: MOdulation / DEModulation • Translates digital   analog ADM2372, M Benyoucef, Fall'08

21. Networkswhat • A network • consists of two or more computers or other intelligent devices linked by communication lines (wired or wireless) • each device is called a node • examples of networks • 2 computers sharing a printer • the Internet ADM2372, M Benyoucef, Fall'08

22. Server Wiring Closet Wiring Closet Floor 1 Floor 2 Basement NetworksLAN • LAN (Local Area Network) • Group of interconnected computers or workstations located in close proximity (e.g., within the same building) ADM2372, M Benyoucef, Fall'08

23. NetworksWAN • WAN (Wide Area Network) • Network of networks • Links geographically distributed computers • Uses broadband public communication services • There is a need to boost and filter the signal • Examples of WANs • Internet, Intranet, Extranet ADM2372, M Benyoucef, Fall'08

24. Networksclient / server (1) • Server: a computer that controls access to shared resources • powerful processor, large memory, large amount of secondary storage • Server hardware (i.e., Dell, IBM, …) • without server software, it is just a client workstation • Server software (MS Server, …) • turns the computer it runs on into a server • Clients • all the other nodes of the network ADM2372, M Benyoucef, Fall'08

25. File System Peer-to-Peer File System Peer File System Peer Peer Networksclient / server (2) Server Printer Client Client File System Client/Server Client Client ADM2372, M Benyoucef, Fall'08

26. NetworksInternet, extranet, intranet Internet extranet intranet ADM2372, M Benyoucef, Fall'08

27. NetworksInternet (1) • The Internet is a public, global communications network that provides direct connectivity to anyone • over a LAN via an ISP (Internet Service Provider) or • directly via an ISP ISP: Internet Service Provider LAN: Local Area Network T1 Line: High-speed telephone line Source: http://computer.howstuffworks.com/web-server3.htm ADM2372, M Benyoucef, Fall'08

28. NetworksInternet (2) • Strategic significance of the Internet • easily accessible • makes communications possible by using protocols • cost-efficient transfer of data • extensive reach + standardization  well suited for conducting business ADM2372, M Benyoucef, Fall'08

29. Networks Intranet (1) • Corporate LAN or WAN that uses Internet technology • Secured behind company’s firewalls • Provides Internet capabilities such as • search engines, browsing, tools for communication & collaboration, etc. • The cost of converting an existing network system to an intranet is relatively low • Employees can get out on the Internet easily • Outsiders cannot get into the intranet ADM2372, M Benyoucef, Fall'08

30. Networks Intranet (2) Server Client Internet Intranet Firewall E-mail Server Web Server Data base ADM2372, M Benyoucef, Fall'08

31. Networks Firewall • Firewall: hardware & software that isolate the company’s intranet from the internet • Controls external access to the company’s servers • Most firewalls work by screening packets • Examples • Only allow packets originating from inside the company • Accept http but no ftp or telnet • Reject MP3 files and adult content ADM2372, M Benyoucef, Fall'08

32. Networks VPN • Virtual Private Network • Provides secure transport of private communications over the public Internet • Less expensive, more flexible, greater bandwidth than non-IP networks • Creates tunnels of secured data flows using encryption • if intercepted, messages cannot be interpreted Internet Point B Point A ADM2372, M Benyoucef, Fall'08

33. What is encryption? Encrypt Cipher Text Clear Text Sender Decrypt Cipher Text Clear Text Receiver • Secret Key encryption • A single key, known to both parties ADM2372, M Benyoucef, Fall'08

34. What is encryption? A simple Caesar-shift substitution Cipher Plain text ATTACK AT DAWN ABCDEFGHIJKLMNOPQRSTUVWXYZ BCDEFGHIJKLMNOPQRSTUVWXYZA BUUBDL BU EBXO Base alphabet Shift one letter Cipher text [ Source: E-commerce Basics, by Davis & Benamati, Addison Wesley, 2003 ] ADM2372, M Benyoucef, Fall'08

35. NetworksExtranet • Network that uses a VPN to link intranets in different locations over the Internet; an “extended intranet” • The protected environment of an extranet allows partners to collaborate & share info securely ADM2372, M Benyoucef, Fall'08

36. The WWW (1) • Before 1990 • E-mail, FTP, telnet • Text based • UNIX commands • 1993: Mosaic • First browser • User friendly, graphical interface • Point & click • Will later become Netscape • 1995: Netscape went public • The WWW (World Wide Web): standardized protocols for creating, naming, linking & accessing Internet content ADM2372, M Benyoucef, Fall'08

37. The WWW (2) Browser • Browser • software that runs on the client’s computer, requests & displays web pages • Web server • software that runs on the host computer and manages web pages • Application server • software that manages the interaction between the web server and the organization’s Information systems Internet Web Server Application Server Organizational Information Systems: Applications & Databases ADM2372, M Benyoucef, Fall'08

38. The WWW (3) • URL (Uniform Resource Locator) • the address of a resource on the World Wide Web http://www.uottawa.ca Top level domain (others: com, org, UK, …) Local domain (others: bell, umontreal, etc.) Hypertext Transfer Protocol: rules used for exchanging web pages between the browser and the web server. Conventional name for the public web server, name of the program that runs on the host ADM2372, M Benyoucef, Fall'08

39. The WWW (4) LAN Server Browser 1 7 2 6 Internet Client workstation 3 5 4 Web Server Web pages Downloading a web page Host Computer ADM2372, M Benyoucef, Fall'08

40. The Wireless RevolutionBluetooth • A wireless networking standard for creating Personal Area Networks (PAN) • Links devices within a 10 meter range • Uses low power radio based communication at up to 722 Mbps ADM2372, M Benyoucef, Fall'08

41. The Wireless RevolutionWi-Fi (Wireless Fidelity) • For wireless LANs • 54Mbps (10 to 30 meters range) • 11Mbps (30 to 50 meters range) • Security issues • Possibility of interferences (from wireless phones, other wireless LANs, etc.) • WiMax (Worldwide Interoperability for Microwave Access) • Range: up to 50 kilometers • Speed: up to 75 Mbps ADM2372, M Benyoucef, Fall'08