1. 1 710: Foundations of Information Systems Chapter 4: Telecommunications And Networks

2. 2 Telecommunication Systems

3. 3 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

4. 4 Media Types

5. 5 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

6. 6 Terminal-to-Host Connection

7. 7 File Server Connection

8. 8 Client/Server Connection

9. 9 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 Client MachineServer Client Program Server Program Request Response

10. 10 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

11. 11 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...

12. 12 Wireless alphabet soup SpecRangeSpeedFrequency 802.11b (WiFi) 75 m11 Mbps2.4 GHz Risks interference w/ cordless phones 802.11a (WiFi-5) 30 m54 Mbps5 GHz Less interference 802.11g75 m54 Mbps2.4 GHz Backwards compatible w/802.11b 802.11i – security standard (authentication and encryption) 802.1x – authentication

13. 13 The Internet Traffic travels across routers between LANs

14. 14 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 standardswww.ietf.org –World Wide Web Consortium (www.w3c.org) sets HTML and HTTP standardswww.w3c.org Backbone network (gigabit connection) –Check http://global.mci.com/about/network/global_presence/global/ (just one company) http://global.mci.com/about/network/global_presence/global/ –Or: http://www.caida.org/tools/visualization/mapnet/Backbones/ 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 * 10 38 addresses)

15. 15 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)

16. 16 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

17. 17 Internet Communication 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)http://www.lsoft.com/lists/listref.html Newsgroups (Usenet) –Go to http://www.google.com/grp hp?hl=en http://www.google.com/grp hp?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

18. 18 World Wide Web (www) 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.comwww.searchenginewatch.com Review Question: What’s the difference between the Internet and the Web? http://www.uwosh.edu Developed in 1989

19. 19 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

20. 20 Worldwide Trends Online Population in million vs. World Population –Online: Jan. 2000 and Feb. 2002, Offline: Mid- 2000

21. 21 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

22. 22 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) –Examples: TitanWeb, Online Banking, E- procurement systems

23. 23 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

24. 24 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

25. 25 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

26. 26 Virtual Private Network

27. 27 Encryption Very important in E-commerce

28. 28 Next Week Lecture –Chapter 5 and 6: E-commerce, Transaction Processing Systems, Management Information Systems, and ERP Presentations –Teams 1, 2 and 3 Assignments –Assignment 2 due from Teams 4 - 8