INT222 - Internet Fundamentals
Shi, Yue (Sunny)
Office: T2095
[email protected]
SENECA COLLEGE
Outline
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Welcome
Course overview
Internet Architecture
Survey
Next class
– JavaScript basics
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Welcome to INT222
• Your Instructor:
– Care
– Diligent
– Open minded
– Willing to help
– Hope you all learn and succeed in your future
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Course Overview
• Seneca Academic Policy:
http://www.senecacollege.ca/academic-policy/index.html
• Course outline:
https://scs.senecac.on.ca/course/int222
• My website:
https://scs.senecac.on.ca/~sunny.shi/
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Course Overview
• Four pillar topics
– Javascript
– HTML5
– CSS3
– DOM
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Course Overview
• Reference material:
o No text book.
o Instructor’s lecture notes,
o Mozilla Developer Network start page
by the Mozilla Developer Network and individual contributors
http://developer.mozilla.org
o Web Education Community Group Wiki
by the W3C Web Education Community Group
http://www.w3.org/community/webed/wiki/Main_Page
o Your Web, Documented
by the W3C and the Web Platform stewards
http://www.webplatform.org/
o My website: (in progress)
https://scs.senecac.on.ca/~sunny.shi/
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Evaluation
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6 labs
10%
2 quizzes
(2% + 3% =)
5%
3 assignments (6% +6% + 8%=) 20%
2 term tests (17% + 18% =)
35%
Final exam
30%
------------------------------------------------Total
100%
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Course Policy
• Assignments & Labs
Late submission: 10% off /each day up to 5 school days
You have to submit all Assignments to get the course credit.
• Tests/ Quizzes:
o No make-up
o With acceptable reason:
- Missing test1:
Your test 1 = (average of class + your test2)/ 2
- Missing test2:
Your test 2 = (average of class + your final)/ 2
- Missing test1 & test 2:
Zero for both
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Communication
• In, before, after class
• Blackboard
• Email:
[email protected]
• Office: T2095 (individual appointment)
•My Website
https://scs.senecac.on.ca/~sunny.shi/
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Evolution of the Internet
• Advanced Research Projects Agency (ARPA) – and the
ARPAnet, by the end of 1969
• Four computers (nodes):
1)
2)
3)
4)
UCLA - University of California, Los Angeles,
Stanford Research Institute,
University of California Santa Barbara
the University of Utah
• Later, other networks, such as the National Science
Foundation’s NSFnet, were created and connected with
the ARPAnet.
• And more…
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7-layer OSI Model
• OSI: Open Systems Interconnection model
– Defines a networking framework to implement
protocols in seven layers.
• Conceptual Model,
– To help better understand complex interactions
that are happening.
• The internetworking is divided into a vertical
stack of seven (7) layers.
7-layer OSI Model
Reference: Image from Internet
7-layer OSI Model
• Control is passed from one layer to the next,
• starting at the application layer in one station,
(Sending)
• proceeding to the bottom layer,
• over the channel to the next station and back
up the hierarchy. (receiving)
7-layer OSI Model
• Example protocols for each layer:
Reference: Image from Internet
Internet Protocol Suite
• Communications protocol:
– a formal description of message formats
– the rules for exchanging those messages
• The communications protocol, Transmissions
Control Protocol / Internet Protocol (TCP/IP),
– proposed by Vinton Cerf and Robert Kahn.
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Internet Protocol Suite
• TCP/IP provides:
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end-to-end connectivity,
reliable,
ordered
error-checked delivery,
• TCP/IP specifies how data should be
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formatted,
addressed,
transmitted,
routed
received at the destination.
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Internet Protocol Suite
• Web browsers use TCP when connecting to servers on the
World Wide Web
• TCP/IP is used to deliver email and transfer files
• HTTP, HTTPS, SMTP, POP3, IMAP, SSH, FTP, Telnet and a
variety of other protocols are typically encapsulated in
TCP.
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Internet Protocol Suite
• Applications that do not require the reliability of a TCP
connection may use the connectionless User Datagram
Protocol (UDP)
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UDP: emphasizes low-overhead operation and reduced
latency
• UDP: no error checking and delivery validation.
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HTTP
• The Hypertext Transfer Protocol (HTTP):
application protocol for distributed, collaborative,
hypermedia information systems.
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HTTP: foundation of data communication for the World Wide
Web.
• Hypertext: structured text that uses logical links (hyperlinks)
between nodes containing text.
• HTTP: the protocol to exchange or transfer hypertext.
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World Wide Web
• Abbreviation: WWW or W3,
• commonly known as the Web
• A system of interlinked hypertext documents that are accessed via the
Internet.
• With a web browser, one can view web pages that may contain text,
images, videos, and other multimedia and navigate between them via
hyperlinks.
• Tim Berners-Lee, a British computer scientist is considered the
inventor of the Web.
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Standards & the World Wide Web Consortium
(W3C)
• The World Wide Web Consortium (W3C):
– main international standards organization for the World
Wide Web.
– in order to continue the development of the web, and its
languages
• Founder: Tim Berners-Lee
• Founded: October 1994
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Web Concepts – URI/ URL
• Uniform Resource Identifier (URI):
– identifies a resource either by location (URL), or a name (URN), or
both.
• URL (Uniform Resource Locator):
– a subset of the Uniform Resource Identifier (URI)
– specifies where an identified resource is available and the mechanism
for retrieving it.
– defines how the resource can be obtained.
– (http://), (https://), (ftp://)
• https://scs.senecac.on.ca/~sunny.shi/index.html
– Protocol: https://
– Domain name: scs.senecac.on.ca
– Document: ~sunny.shi/index.html
DNS (Domain Name System/Server)
 DNS: names to IP addresses. DNS servers (name servers)
associate the domain names with the IP address
 e.g.
zenit.senecac.on.ca is used to identify IP address 142.204.140.203.
 In addition to ".ca", other common domains include
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.com - commercial
.edu - educational
.gov - governmental
.net - isp
.org - non-profit
and many more
 ICANN (Internet Corporation for Assigned Names and Numbers) - oversees
assignment of names and IP addresses and certifies domain name registrars
to manage the process.
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client-server computing (C/S) model
Client Side
Web
Browser
Server Side
Server response
Web Server
pages
HTTP request
scripts
programs
Multimedia files
…….
DataBase
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Web Application
• A web application or web app:
– Any application software that runs in a web browser
– is created in a browser-supported programming language (e.g.,
JavaScript, HTML, CSS)
– relies on a web browser to render the application.
• sometimes called a thin client.
• Update and maintain web applications without distributing and installing
software on potentially thousands of client computers
• inherent support for cross-platform compatibility.
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Web Application
• Common web applications include:
– Webmail
– Online retail sales,
– Online auctions
– Wikis
– Many more…
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Next class
• JavaScript basics
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Thank you!