Local Area Networks

1
Local Area Networks

• Local Area Network (LAN) is a network of machines
  covering a
  limited geographical
  area
• Metropolitan Area
  Network (MAN)
  covers more densely
  populated area

2
Wide Area Networks

• Wide Area Network
  (WAN) covers multiple
  locations, each of which
  consists of a LAN or
  a MAN
• LANs and WANs are
  often private networks

3
The Internet as Global WAN

• The Internet is the worlds largest network
• Links millions of businesses, governments,
  educational institutions, and individuals

4
Internet Protocols

• What is a protocol ?
• A protocol describes how communication should
  take place (e.g. Roberts Rules of Orders)
• Internet transmits data using two protocols
• Transmission Control Protocol (TCP) provides
  error handling, packet resubmission, etc.
• Internet Protocol (IP) provides low-level
  communications

5
Accessing Web Pages
6
World Wide Web

• World Wide Web (WWW)
• Invented by Tim Berners-Lee in early 1990s while
  at CERN (now at MIT)
• Web is decentralized and runs on top of the
  Internet
• Building blocks of the Web
• HyperText Transfer Protocol (HTTP)
• Uniform Resource Locator (URL)
• HyperText Markup Language (HTML)

7
Uniform Resource Locators

• Uniform Resource Locator (URL) identifies the
  protocol, domain (machine) name, and file path of
  resource being requested
• http//academic2.strose.edu/math_and_science/golds
  chd

8
HyperText Markup Language

• HyperText Markup Language (HTML) defines page
  layout, fonts, links, text, etc.
• HTML tags describe how Web browsers should
  display text
• lthtmlgt
• lttitlegtWelcome to The College of Saint
  Roselt/titlegt
• ltbody bgColorgray textblackgt
• ltimg srcpeople.gif width184 height119gt
• ltpgtWelcome to The College of Saint Rose.
• lta hrefhttp//www.cnn.comgtClick here for
  news.lt/agt
• lt/pgt

9
Web Site Design Process

• Steps to building a Web site
• Define objectives and intended audience of the
  Web site
• Select the content to be presented
• Determine the navigational structure and layout
• Construct the individual Web pages
• Test your Web site (proofread content, verify
  links)
• Obtain server space and a URL
• Publish, then publicize, your Web site
• Keep Web page content up-to-date

10
Web Site Design

• A Web site consists of many individual Web pages
• Web pages within a site usually have a consistent
  look and feel or user interface layout
• Achieve a consistent user interface layout by
• Copying-and-pasting the same HTML code from one
  HTML file to another
• Using JavaScript to generate the same HTML code
  on each Web page
• Designing a Web site using the ltFRAMESgt tag

11
Domain Name Registration
12
Graphics on the Web (i)

• Graphics available on the Web in many different
  formats

13
Graphics on the Web (ii)

• Graphics embedded in
  Web pages using HTML

14
Saving Images

• After finding an image, right-click on it, then
  select Save Picture As... or Save Image As...