EN3515 Address 4: Systems administration and the Web - PowerPoint PPT Presentation

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EN3515 Address 4: Systems administration and the Web

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  1. EN3515 Lecture 4:Networking and the Internet Net Spaces Case Studies Network Hardware Network Software Network Standards/Protocols Internet Communication Strategies Evaluating Good Websites

  2. Net Spaces The landscape of Cyberspace The Matrix (main part of cyberspace] The Internet • FTP space • Telnet space • Gopher space • WAIS space • Web space • Email space Usenet BITNET Commercial Services Private Nets

  3. Cyberspace: The Matrix

  4. FTP Space The set of all resources accessible through the File Transfer Protocol on the Internet. The resources include directories of files and individual files that might be text or binary (executables, graphics, sound, and video) files. It is among the oldest spaces on the Net and has massive and often obsolete and polluted information on it. It is a major distribution area for software. Recent trend of Files Transfer on Internet: P2P

  5. FTP Keyword Searcher There is no way to search the contents of documents at FTP sites. The only alternative is to use Archie--a tool that indexes the filenames at FTP sites and is good for looking for a software or shareware program of a particular name. Most of these “old world” Internet resources are integrated by WWW today.

  6. Telnet Space Telnet is a protocol for remotely logging into a remote computer. Many Telnet sites still offer valuable and updated information (i.e. card catalogs of libraries). Using Telnet, you can also access your own e-mail account from a long distance. Example: Telnet://personal.cityu.edu.hk

  7. Gopher Space Gopher, an information system designed at the University of Minnesota, is among the oldest spaces on the Net. Because of the rise of the Web, the Gopher traffic on the Net has declined. Here is the mother of all Gophers at the University of Minnesota http://www.webopedia.com/TERM/g/gopher.html

  8. Gopher Subject Tree A good collection of subject-related Gophers is “Gopher Jewels.” A Web-version is at: http://galaxy.einet.net/GJ/index.html The Internet search engine history: http://www.galaxy.com/info/history2.html

  9. Case Studies Build a peer-to-peer LAN Build a client-server LAN Build New Media Lab LAN From CityU to Internet

  10. Build a Peer-to-Peer Network Minimal items needed: • 2+ computers, each with a network card • a crossover cable, or a cable and a hub • Windows 3.11/95/98 on all computers (or crossover cable) Hub

  11. The buzz word of peer-to-peer network (P2P): kazaa • http://www.download.com #1 download!! • Let’s do a search on wired.com with “kazaa” server

  12. Server/Client Network Minimal items needed: • a server with networking software • 2+ workstation • a hub (or switch) • Network cables Link to outside network(s) Server

  13. New Media Lab LAN (example) • Servers: • NT server: primary controller, printer server, file server, and secondary Web server • Win2000 server: primary Web server • Workstations: • 28, running Windows XP, with some of these connected to overhead projector, sound system, scanners, CD-writers, and video conferencing systems

  14. The NML LAN (2) • Servers, workstations, and printers are connected through 100BASE-T cable (100mps) to designated ports on LAN switches • The Lab LAN is connected to the Internet via CityU ATM backbone network (154mps) • A router shields the Lab LAN from CityU-EN LAN (i.e., making the Lab a subnet of the LAN), to separate the resources/broadcast messages between the two LANs

  15. The NML LAN (3) CityU Staff LAN scanner Internet EN Staff LAN V-Con NT Unix Router 24-port Switch 16-port Switch V-Con scanner

  16. From LANs to Internet

  17. From CityU to the Internet Media Lab

  18. Network vs. the Internet • Network • LAN (private, closed system) • WAN (LAN extended to a larger area) • Intranet, Extranet, and the Internet • Intranet (LAN or WAN using Internet connection): Example: CityU Portal • Extranet (Intranet extended to associates) • The Internet (a public, open system)

  19. Internet vs. World Wide Web • Internet is the physical infrastructure on the global scale whereas WWW is one of the following protocols (i.e., software standards) that run on the Internet: • http (for WWW) • ftp (file transfer protocol) • telnet (remote login protocol) • gopher (text-based WWW) • mailto (e-mail)

  20. Networking Standards • Protocol for connection • TCP/IP (most popular) • IPX (Novell’s proprietary system) • NetBIOS/NetBEUI (easy, fast, from Microsoft, for P2P LANs) • IP Address • Classes (c.l.l.l; c.c.l.l; c.c.c.l) • Default gateway (usually the last # in the net) • Subnet mask (usually

  21. IP Address • An IP address is a unique identification for any computer connected to the Internet. • All IP addresses are in the form of x.x.x.x (where x has 8 bits & ranges from 0 to 255). • IP addresses are assigned at levels: • Global authority: Network Solutions, Inc. • Local authority: the network administrator of your organization

  22. Classes of IP Address

  23. IP Address vs. Internet Address • IP address (a 4-quad numeral) identifies a computer connected to the Internet (e.g., 144.214.44.x for our NT server) • Internet address (a literal of any length) identifies a Web server (e.g., newmedia.cityu.edu.hk for the NT server) or a subdirectory of a Web server (e.g., newmedia.cityu.edu.hk/en5611) • Web server can be a server or a workstation with a fixed IP address and a hardwire connection

  24. Dynamic IP Address and Dial-up Connection • A dynamic IP address is assigned by a network server during the connection time (often through a dial-up means) • A computer is typically assigned a different dynamic IP address each time connected • Dial-up connection involves modem-phone line (up to 56kps), or ISDN (Integrated Service Digital Network, 128kps), or ADSL, xDSL, or cablemodem…

  25. Next Generation of IP Address: IPv6

  26. IP Address

  27. Other trend of WWW • Connect to the next PPT file…

  28. Internet Communication Fundamentals & Strategies • Effects: a communication perspective • Unique features of the Internet (Web) as a communication medium • Web design: setting reasonablegoals • Types of Web design • Basic elements of good Web Sites • Do’s and don’ts in Web design

  29. Effects: A Communication Perspective A simple hierarchy of communication effects: • Behavior(actions, performances) • Attitude(beliefs, values, opinions, judgments) • Emotion(feelings, likes) • Cognition (knowledge, information, thinking process)

  30. Effective Communication Communication that comes from trusted sources, reaches the targeted audience with appropriate format (means and channels) and content, and achieves the intended goals.

  31. Unique Features of Internet as a Communication Means Although the Internet has “inherited” some features from the traditional media, it is distinct in several ways: • Interactivity • Non-linearity (hypertext and hyperlink) • Multimedia capability • Porous quality (in pieces) • Varying speed (connection speed dependent) • Varying browsers (IE, Netscape, Mozilla, Opera, etc.) • Varying display (monitors, mostly 14” and 15”) • Almost unlimited choices (too many possible links!!)

  32. The 28.8Kbps Factor About one-third of the people using the Internet are connected through 28.8Kbps modems. A bit -- a contraction of the phrase binary digit --is the most elemental unit of computer information, either a 1 or a 0. One byte is made up of 8 bits. Therefore, a 75KB (75,000-byte) file would take 20.8 seconds to transfer at 28,800 bits per second.

  33. Web recent trend From text-based, to more graphically-represented. From more passively transfer information, to more “interactive,” or even more “immersive” (immersed) Example: http://flysworkshop.net/as/ Example: http://www.activeworlds.com/ or http://www.worlds.com

  34. Internet Communication Goals General goals: • Information • Entertainment • Service • Marketing • Persuasion • Pure presence

  35. Internet Communication Goals(Marketing) Some specific goals in marketing: • Brand-building • Direct marketing • Online sales • Customer support • Market research • Content publishing/services

  36. Three Major Types of Web Sites • Brochureware • Show-biz • Utilitarian

  37. Brochureware Brochureware sites are the most commonly deployed ones on the Web. They are normally static, non-interactive and boring “about-my-business”sites. http://www.spam.com/

  38. Show-biz Show-biz sites mean two things: First, those misguided attempts to lure visitors to shows of products; second, flashy and showy sites that feature technical dexterity. Example: Lipton’s margarine http://www.tasteyoulove.com/

  39. Utilitarian Utilitarian sites are those that offer Web surfers a genuine service and experience -- an interactive information/service utility. Federal Express’s (FedEx) site is a classic example.

  40. Schools of Web Design • Early ASCII: text • Classic: three-part Web page • Modern: graphic slabs • Postmodern: fragments • Early virtual: 2D/3D scene, metaphor

  41. Early ASCII: Text Influenced by the hierarchical organization common in previous information systems such as Gopher, FTP and Telnet, the early ASCII design style relies heavily on hierarchical organization and links to extend meaning. This school is obsolete. Example: a telnet web page design.

  42. Early ASCII Page Example

  43. Classic: Three-Part Web Page The classic three-part structure of head, body and column is popular with the use of graphical browsers because the visual impact of a single screen has more visual impact that the scrolling browsers, such as the Lynx browser. Example: our course site

  44. Modern: Graphic Slabs Marked by the use of graphics to draw attention, reveal choices and provide ornament, this style runs the gamut of expressions ranging from a single-graphic slab to a mixture of graphics and text often arranged in a grid to reveal functionality. Examples: compare whitehouse.gov and amazon.com

  45. Postmodern: Fragments Instead of conceiving a page as a fixed structure, a postmodern style generates a page based on user requests by the use of CGI programming to dynamically create web pages and graphics on the fly. Example: HotWired (http://www.hotwired.com/members/)

  46. Early Virtual: Scene The early virtual page involves Virtual Reality Modeling Language (VRML) and can be viewed as an environment in which the room or the scene becomes a unit of attention for the user. • VRML • Adobe Atmosphere • Digital Space • Activeworlds..etc. http://www.taj-mahal.net/blackBack.htm

  47. Elements of Good Web Sites • Good sites are good communities • Good sites are relevant (e.g. personalized content) • Good sites entertain (pleasing) • Good sites do not stand alone (linked)

  48. Some Do’s in Web Design • Know your audience • Build in interactivity and feedback (when necessary) • Provide good and user friendly navigation • Create consistent, pleasing and efficient look and feel • Keep files short and small (45KB or below per page) • Content, content, content • Link to most relevant resources • Use graphics and multimedia only when they are necessary and efficient

  49. Some Don’ts in Web Design Avoid: • monster page overloaded with information • multimedia overkill example1 • meaningless links • clown pants (disorganized pages) • KOOL design (overly fancy but empty sites) sukers worst websites

  50. Evaluating Standards and Strategies (1) Basic assessment: The Internet is an invaluable source of information, communication, and interaction. It contains diverse information, some of which is good and some of which is garbage.