3. Internet
៚ A short form of the technical term internetwork and also referred to as Net
៚ A global system of interconnected computer networks that use the standard
Internet Protocol Suite (TCP/IP)
៚ A network of networks that consists of millions of private, public, academic,
business, and government networks, of local to global scope, that are linked by
a broad array of electronic, wireless and optical networking technologies
៚ Carries a vast range of information resources and services
៚ Services over Internet
៙ Web (WWW)
៙ E-commerce
៙ Communication (e-mail, forum, chat, telephone, etc.)
៙ File transfer
៙ Online learning, working
៙ Remote connection, etc.
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5. Protocols
៚ Open Systems Interconnection model simplified (OSI model)
៙ Application: HTTP, FTP, POP, IMAP, SMTP, DNS, SSH, etc.
៙ Transport: TCP (Transport Control Protocol), UDP (User Datagram
Protocol)
៙ Network: IP (Internet Protocol)
៙ Data Link: no specified
៚ Application Layer
៙ HTTP (HyperText Transfer Protocol): Web
៙ FTP (File Transfer Protocol): file transfer
៙ POP (Post Office Protocol)/IMAP (Internet Message Access Protocol),
SMTP (Simple Mail Transfer Protocol): e-mail
៙ DNS (Domain Name Server): translating hostnames into IP address
៙ SSH (Secure Shell): remote secure connection
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6. History
៚ 1959-68: ARPA Project, Ministry of Defense of America launched a network to
support the consequences of the nuclear conflict.
៚ 1969: ARPANET network, universities of America were installed lots of
computers that were connected to the network.
៚ 1970-82: Open world wide, the first connection with Norway and London
៚ 1983: Internet via TCP
៚ 1986: Highway of information, National Science Foundation deployed super-
computers for speeding up the debit of Internet.
៚ 1987-92: Expansion of Internet, private companies were connected to Internet.
៚ 1993-2003: Explosion of Internet (Web and e-mail)
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8. Web
៚ World Wide Web, abbreviated as WWW and commonly known as Web
៚ A system of interlinked hypertext documents accessed via Internet
៚ Client/Server Model
៚ Based on 3 concepts:
៙ Location: URL (Uniform Resource Locator)
៙ Protocol: HTTP
៙ Language: HTML (HyperText Markup Language)
៚ Functions:
៙ Clients communicate with a web server via HTTP.
៙ Servers verify the request and authentication, and transmit the responses.
៙ Web browsers interpret the responses and display (maybe with a plug-in).
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9. History
៚ Origin
៙ Birth of CERN: A requirement to exchange of documents, photos, etc.
៙ 1989: Network of Document by Tim Berbers-Lee
៙ 1990: The first prototype in text mode
៙ 1991: The demonstration at Hypertext 91 by San Antonio
៚ Evolution
៙ 1993: The first Mosaic GUI by Marc Andreesen
៙ 1994:
ៜ Netscape Com. Corp. by Marc Andreesen
ៜ WWW Consortium (W3C) by Tim Berbers-Lee after leaving CERN and
founded by MIT
៙ 1996: Cascading Style Sheet (CSS)
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10. Document Address
៚ Uniform Resource Locator (URL):
៙ A URI that specifies where an identified resource is available and the
mechanism for retrieving
៙ 3 parts:
ៜ protocol (how)
ៜ domain (hostname or IP) (where)
ៜ file name (which)
៚ URI:
៙ A string of characters used to identify a name or a resource on the Internet
៙ One can classify URIs as locators (URLs), or as names (URNs), or as both.
៚ Uniform Resource Name (URN): defines an item's identity, while the URL
provides a method for finding it.
៚ i.e.
៚ http://www.google.com/index.html
៚ http://www.xyz.com/x%20y%20z%20.html (with URL encoding)
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11. Document Address (cont.)
៚ Different components of a URL:
៙ proto://domain:port/path?args
៙ proto: protocol (http, https, ftp, etc.)
៙ domain: hostname or IP
៙ port: port number (80 for http, 443 for https, etc.)
៙ path: maybe contains a fragment
ៜ i.e. http://en.wikipedia.org/wiki/Internet#Protocols
៙ args: allows to pass information to server-side applications
ៜ i.e.
http://www.google.com/search?hl=en&source=hp&q=Int
ernet&aq=f&aqi=g10&aql=f&oq=
៚ URL path:
៙ Relative : img/xyz.png (a link in
http://www.xyz.com/index.html)
៙ Absolute path: http://www.xyz.com/img/xyz.png
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12. Web Page, Web Site & Web Browser
៚ Web page (or webpage):
៙ A document or information resource that is suitable for the World Wide
Web and can be accessed through a web browser and displayed
៙ This information is usually in HTML or XHTML format, and may link to
other web pages via hypertext links.
៙ Web pages frequently subsume other resources such as style sheets,
scripts and images.
៚ Web site (website):
៙ A collection of related web pages containing images, videos, etc.
៙ A web site is hosted on at least one web server, accessible via a network
such as the Internet or a private local area network through a URL.
៚ Web browser (or Internet browser): a software application for retrieving,
presenting, and traversing information resources on the World Wide Web
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13. During displaying the content, a web browsers request other resources such as
images, music, etc.
Static Web Page
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15. Proxy
៚ Proxy server:
៙ A server (a computer or an application) that acts as intermediary between
clients and servers
៙ Most proxies are a web proxy, a;;owing access to content on the web.
៚ Potential purposes of a proxy:
៙ Keep machines behind it anonymous (security)
៙ Speed up access to resources (cache)
៙ Apply access policy to network services or content, i.e. block undesired
sites
៙ Log or audit usage, i.e. provide company employee Internet usage
reporting
៙ Bypass security or parental controls
៙ Scan transmitted content for malware before delivery
៙ Scan outbound content, e.g., for data leak protection
៙ Circumvent regional restrictions
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17. Internet and internet is Sometimes someone asks
different because of I and i. me to install some plug-ins.
It’s annoying.
Cool.
You’re idiots.
I don’t care. Internet and web is the same.
I go to suffer Internet or web.
Go to school again, IE.
This web page is COOL.
When it’s with me, why is its
presentation DIFFERENT?
What are web 1.0 and web 2.0?
I know. You’re HOT.
Ask my developers Google.
I know that I don’t know. Write one page and send to
your teacher.
Comic
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