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311: Management Information Systems

311: Management Information Systems. Chapter 4: Telecommunications And Networks. Telecommunication Systems. GHI. DEF. “Connect to GHI”. ABC. MNO. JKL. Network. A Network is an Any-to-Any Communication System Can connect any station to any other

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311: Management Information Systems

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  1. 311: Management Information Systems Chapter 4: TelecommunicationsAnd Networks

  2. Telecommunication Systems

  3. GHI DEF “Connect to GHI” ABC MNO JKL Network • A Network is an Any-to-Any Communication System • Can connect any station to any other • Each Station has a Unique Network Address • To connect, only need to know the receiver’s address • Like telephone number

  4. Transmission Media • Twisted-Pair Wire • Telephone wire, Cat 5 • Coaxial Cable • Cable TV cable • Fiber-Optic Cable • 20 x price of twisted pair, 1000 x capacity • Microwave Signals • ’No, you don’t get toasted!’ • Satellites, line-of-sight • Infrared and Radio Signals • Wireless, short distance

  5. Media Types

  6. Data Processing Strategies • Centralized Processing • all processing occurs in a single location or facility • Decentralized Processing • processing devices are placed at various remote locations • Distributed Processing • computers are placed at remote locations and connected via telecommunication devices

  7. Terminal-to-Host Connection

  8. File Server Connection

  9. Client/Server Connection

  10. Client/Server Processing • Cooperation Through Message Exchange • Client program sends Request message, such as a database retrieval request • Server program sends a Response message to deliver the requested information or an explanation for failure Server Program Client Program Request Response Client Machine Server

  11. Networks • Local Area Network (LAN) • Connect computers in a single building or campus • Distances typically less than 1,000 meters • Wide Area Networks (WAN) • Connects computers across long distances • Typically several hundred kilometers • Example: Internet • Metropolitan Area Networks (MAN) • Connects computers in the same city • Up to 100 kilometers (often much less) Not in Book

  12. Network Types • Ethernet • Very popular, Cheap 10/100/1000 Mbps • Usually short distances • Asynchronous Transfer Mode (ATM) • Good for multimedia. Used for Internet access. • Up to 622 Mbps over long distances • Bluetooth • For connecting devices (printer, mouse etc) to PC. Short range, piconet, Max 1 Mbps • More wireless on next slide...

  13. Wireless alphabet soup • 802.11i – security standard

  14. The Internet Traffic travels across routers between LANs

  15. Technological Underpinnings • Internet Management • No owner! Managed by negotiation and non-binding contracts. May not continue to work. • Internet Engineering Task Force (www.ietf.org) decides on technical standards • World Wide Web Consortium (www.w3c.org) sets HTML and HTTP standards • Backbone network (gigabit connection) • http://www.caida.org/tools/visualization/mapnet/Backbones/ • Network Addressing • IP numbers: e.g. 140.252.13.33 (32 bits = 4 billion addresses) • The internet is running out of addresses! • Long-term solution: IP v6 (128 bits = 3.4 * 1038 addresses)

  16. More Technology… • Domain Names • Text version of IP address (translated by DNS) • Country domains (.dk, .uk, .de, .us) and generic domains (.com, .net, .org). USA also has .mil, .gov, and .edu. • NEW: .aero, .biz, .coop, .info, .museum, .pro, .name • Managed by ICANN (www.icann.org) • Network Access • No-one controls access! • Most people connect through an ISP • AOL and MSN largest ISPs (even though they are Online Services (OLSs)

  17. Internet Protocols • Internet Protocol (IP): standard that enables traffic to be routed from one network to another as needed • Transport Control Protocol (TCP): rules that computers on a network use to establish and break connections • Uniform Resource Locater (URL): an assigned address on the Internet for each computer

  18. E-mail (first time in 1971!) One of the most popular activities on the Internet! Becoming official business communication mode ListServ (http://www.lsoft.com/lists/listref.html) Newsgroups (Usenet) Go to http://www.google.com/grphp?hl=en Being outpaced by web-based fora Telnet FTP Streaming Internet Radio, Internet TV Real-Time Streaming Videoconferencing Chatting/IM Online collaboration Internet Telephony (VoIP) Web log (blog) Rich Site Summary (RSS) a.k.a. RDF Site Summary Internet Communication

  19. World Wide Web (www) Developed in 1989 • Hyper Text Transfer Protocol (HTTP) • Hyper Text Markup Language (HTML) • And derivatives/alternatives • SGML, DHTML, XML • URL • Browser • Search engines • Google most popular • Categories: Web crawlers (e.g. Google), categorized (e.g. Yahoo), Meta-search (search many engines) • Info on search engines: www.searchenginewatch.com • Review Question: What’s the difference between the Internet and the Web? http://www.uwosh.edu

  20. Types of Internet sites • Portals • A unified access site for many different sites (e.g. Excite, Yahoo, ...) • Can be topical (webMD), geographical (www.denmark.dk) • E-commerce • Government • Special Interest Groups • Informational • ...

  21. Internet Worldwide Trends • Rapid worldwide growth continues • Main use in • North America, Europe, Australia • Some use in • Asia, Middle East, Eastern Europe, South America • Virtually no use • Africa (90% in South Africa) • 80% of all international connections from Asia, Africa, S. America go directly to a US city

  22. Worldwide Trends • Online Population in million vs. World Population • Online: Jan. 2000 and Feb. 2002, Offline: Mid-2000

  23. Intranets and Extranets • Intranet • An internal corporate network built using Internet and World Wide Web standards and products; used by the employees of the organization to access corporate information. • Extranet • A network that links selected resources of the intranet of a company with its customers, suppliers, or other business partners; based on Web technologies. • Accessed by on-site employees • Passwords needed • Most company info can be put on intranet • Accessed by off-site employees and business partners • Passwords needed • Example: Online banking, TitanWeb

  24. Intranet and Extranet • Both use internet standards • Web pages, HTTP-protocol • Intranet • Within a company • Extranet • Outside access to a company’s intranet or specific web pages • Security: Virtual Private Networks (VPN)

  25. Electronic Data Interchange (EDI) • A system to electronically transfer business documents • Orders, bills, confirmations etc • ’Structured e-mail messages’ • Agreements/partnerships are set up in advance

  26. Issues in EDI • Data Standards • ANSI X.12: Used in the US • EDIFACT: Defined by UN. Used in much of the rest of the world • XML/EDI may help in the future • http://www.geocities.com/WallStreet/Floor/5815/ • Companies must use the same standard to communicate • Standards can be tailored to fit industries or individual businesses • Mostly for large companies • May force smaller business partners to use EDI

  27. Issues in EDI • Two Network Standards • Value Added Network (VAN) • Pro: High security, high capacity • Con: Price, incompatible hardware, only large companies • Internet • Pro: Cheap, ubiqutous, easy to use • Con: Security, capacity

  28. Virtual Private Network

  29. Ensuring Security of Information and Access • Firewalls • Security Management • Organizational procedures • Encryption and digital signatures • Secure Protocols • E.g. HTTPS

  30. Encryption Encryption: a process of making messages indecipherable except by those who have an authorized decryption key

  31. Single-key encryption • The sender of the electronic message (or payment) encrypts the information with a key • The receiver uses an identical key to decrypt the information to a readable form • The same code has to be in the possession of both the sender and the receiver • Problems: if a key is transmitted or intercepted illegally, it could be used to read all encrypted messages

  32. Public/private key encryption • Two different keys - public key and private key • Several authorized people may know the public key, but only its owner knows the private key • Every person has one private key and one public key • Encryption and decryption can be done with either key • If encryption is done with the public key, the decryption can be done only with the private key and vice versa • Problem: Slower than single-key encryption • Try it out: go to http://www.pgp.com/products/freeware.html • Freeware version: No commercial use! • 8.6 MB download

  33. Public/Private Key Encryption

  34. Coming Up • Thursday • Lab 4 due • Tuesday • Lecture on Chapter 5 • Note: GUI has been moved

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