Transcript Internet

Internet Applications
Theory & Applications
Internet Applications
- Ibrahim Otieno [email protected]
+254-0722-429297
SCI/ICT Building 2nd Floor Rm. 201
ICS 622 - Delivery
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ICS 622 - Delivery
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ICS 622 – Course Text
 Douglas Commer, Computer Networks and
Intranets, (New Jersey, Prentice Hall)
 Deitel and Deitel, Internet and World Wide Web
How to Program, Prentice Hall
 E. Loren Buhle et. Al., Webmasters's Professional
Reference, (New Riders Publishing)
 Scott Hillier and Daniel Mezick, Programming Active
Server Pages, (Washignton, Microsoft press)
Course Outline
History of the Internet
Internet Protocols
Internet & Communication protocols
Internetworking
TCP/IP Applications
Web Application Design & development
Web site Administration and Internet
Security
 Cloud Computing
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Objectives
To describe the Internet Technology
 To appreciate the development of the
Internet
 To understand the theory, role and
applications of the Internet
 To develop Web Applications
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Introduction
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What is the Internet?
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What protocols are used?
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What is a computer network?
◦ Interconnected, communicating and sharing data
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Types of Computer Networks?
◦ LAN, CAN, MAN,WAN
Introduction
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Network Topologies?
◦ Star, Bus, Ring
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Technologies in WAN
◦ Circuit switching, Packet switching
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Internet, Intranet and extranet
TCP/IP Overview
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Network protocols are formal rules of behavior
that govern network communication
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Specifies format and meaning of messages
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Set of related protocols designed for compatibility
referred to as protocol suite.
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Transmission Control Protocol (TCP) and Internet
Protocol (IP) are two communication protocols
encompassed by Internet Protocol Suite
TCP/IP Overview

Protocol suite referred to as TCP/IP as TCP &
IP are two most important protocols of
collection
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Other protocols include: UDP, ICMP, FTP, HTTP
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TCP/IP has a set of standards specifying how
computers communicate and how routing is done
through the interconnected computers
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Provides two primary services: connectionless
packet delivery and reliable stream transport
TCP/IP Overview …cont’d
TCP/IP has been made popular because of these
features:
1. Network Topology Independence - TCP/IP is
used on bus, ring, and star networks.
It’s used in LANs as well as WANs
2. Physical Network Hardware
Independence - TCP/IP can utilize Ethernet,
token ring, or any number of physical hardware
variations.
TCP/IP Overview …cont’d
3. Open Protocol Standard - The TCP/IP
protocol suite standard is freely available for
implementation on any platform (H/W & O/S).
4. Universal Addressing Scheme - Each
computer on a TCP/IP network has unique
address enabling any TCP/IP enabled device to
communicate with it.
5. Powerful Client-Server Framework TCP/IP is the framework for powerful and
robust client-server applications that operate in
LANs and WANs
The Internet
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Internet is a worldwide system of
interconnected computers and computer
networks that use the TCP/IP protocol suite
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Internet is a network of networks, linking
computers to computers sharing the TCP/IP
protocols. Each runs software to provide
information and/or to access and view
information
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At a basic level Internet is a global computer
of networks, that allows millions of machines to
communicate with each other
The Internet
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Internet is a worldwide tele-communications
system that provides connectivity for thousands
of other smaller networks; therefore, often
referred to as a network of networks
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The Internet is a worldwide network of
thousands of linked computers compared to "a
giant international plumbing system"
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The Internet is actually millions of computers
connected together in some way (phone lines,
Ethernet, ISDN, cable modems) so that they can
share information.
The Internet …cont’d
Packets/ Headers/ Routing/ Error Correction/ Reassembly
The Internet …cont’d
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The metaphor of roads:
Side roads run through neighborhoods, linking
different parts, linking individual building together
 Small roads in turn connect to large ones
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Each building is a different computer on the
internet with it own function - government offices,
educational institutions etc.
The Internet …cont’d
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The metaphor of roads:
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Roads are network connections that link buildings
together. Vehicles travelling along them are data
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Data can be sent from one computer to another
no matter where they are physically
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Note: Internet is not just one gigantic computer
with all of the information;
The Internet …cont’d
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Compared to international communication utility
servicing computers
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Nodes connected through routers "gateways",
and share a common name and address space
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Internet is revolutionizing communication and
changing the way we work and play
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Internet is transport vehicle for info stored in
files or documents on other computers
The Internet …cont’d
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By 1993, Internet included 10,000 IP networks
interconnecting more than 1m computers and
millions of users
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The Internet itself does not contain information
Misstatement - "document found on the
Internet."
 Correct - found through or using the Internet
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Found in/on one of computers on the Internet
History of the Internet
1957: The USSR launches Sputnik, first artificial
earth satellite.
 US forms the Advanced Research Projects Agency
(ARPA) within the DoD to establish US lead in
science and technology applicable to the military
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1962: J.R. Licklider of MIT, propose a global
network of computers. Leonard Kleinrock of MIT
and later UCLA developed the theory of packet
switching
History of the Internet
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1962: Paul Baran, of RAND Corporation
commissioned by the U.S. Air Force to do a study
on how it could maintain its command and control
over its missiles and bombers, after a nuclear attack
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His final proposal was a packet switched network:
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Packet switching is breaking of data into packets
Labeled to indicate the origin & the destination
Forwarding of packets from one computer to another
computer to its final destination computer
If packets lost, message can be resent by originator
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History of the Internet …cont’d
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1968: ARPA awarded ARPAnet contract to BBN
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BBN selected a Honeywell mini-computer as base
on which they would build the switch
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Physical network constructed in 1969, linking four
nodes: University of California at Los Angeles, SRI
(Stanford), University of California at Santa
Barbara, and University of Utah.
History of the Internet …cont’d
1972: First e-mail program created by Ray Tomlinson
of BBN.
 ARPA renamed to DARPA.
 ARPANET was using NCP to transfer data
 Communications between hosts on same network
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1973: Development began on TCP/IP
Developed by a group headed by Vinton Cerf from
Stanford and Bob Kahn from DARPA.
 Protocol was to allow diverse computer networks to
interconnect and communicate with each other
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History of the Internet …cont’d
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1974: First use of term Internet by Vint Cerf and
Bob Kahn in paper on TCP
1976: Robert M. Metcalfe develop Ethernet, which
allowed coaxial cable to move data fast
 Crucial component to development of LAN
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UUCP (Unix-to-Unix CoPy) developed at AT&T
Bell Labs and distributed with UNIX one year later
 DoD began to experiment with TCP/IP and
decided to require it for use on ARPANET
History of the Internet …cont’d
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1979: USENET based on UUCP created by Steve
Bellovin
Creation of BITNET, by IBM, "Because its Time
Network", introduced "store and forward" n/w
Used for email and listservs
1981: NSF created backbone called CSNET for
institutions without access to ARPANET
1983: Internet Activities Board (IAB) created. January
1st , every machine connected to ARPANET had to use
TCP/IP replacing NCP
University of Wisconsin created DNS
Allowed packets to be directed to domain name
making it easier for people to access servers
History of the Internet …cont’d
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1984: ARPAnet divided into two networks:
MILnet and ARPAnet
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DoD continued to support both networks
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1985: NSF began deploying its new T1 lines,
which would be finished by 1988
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1986: IETF was created to serve as a forum for
technical coordination by contractors for
DARPA working on ARPANET, US Defense
Data Network (DDN), and the Internet core
gateway system.
History of the Internet …cont’d
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1987: BITNET and CSNET merged to form the
Corporation for Research and Educational
Networking (CREN), another work of NSF
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1991: CSNET was discontinued having fulfilled
its important early role in the provision of
academic networking service
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1992: Internet Society is chartered and WWW
released by CREN.
History of the Internet …cont’d
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1993: InterNIC created by NSF to provide specific
Internet services: directory, database, registration, and
information services
Marc Andreessen, NCSA and University of Illinois
develops a GUI to the WWW, called "Mosaic".
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1994: The most significant thing was growth.
Pizza Hut offers pizza ordering on its Web page and
the first cyberbank, opens.
ATM (Asynchronous Transmission Mode) backbone is
installed
History of the Internet …cont’d
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1996-DATE: Internet traffic carried by backbones
of ISPs, including MCI, AT&T, Sprint, UUnet, BBN
planet, ANS, and more.
Currently Internet Society(ISOC) is the group that
controls devpt and availability of internet
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Trying to figure out new TCP/IP to be able to have
billions of addresses, rather than the limited system
of today
Problem is that not known how both old and new
addressing systems will work at the same time
during a transition period
Internet Usage
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Number of users has grown from an estimated 38m in 1994 to 101m
in January 1998 and over 400m in December 2000, 580m in May
2002 and 1.6 b in June 2009 and 2 b in 2011.
Distribution of Internet Users (millions) (178M Sites)
Dec 2000
May 2002
USA/Canada177.78 (42.5%) 182.67 (31.4%)
Europe
133.97 (32.0%) 185.83 (32.0%)
Asia/Pacific 104.88 (25.1%) 167.86 (28.9%)
Latin America
16.45 (3.9%)
32.99 (5.7%)
Africa
3.11
(0.7%)
6.31
(1.1%)
Middle East 2.40
(0.6%)
5.12
(0.9%)
TOTAL
418.59
580.78
Internet Usage
Internet Usage
Internet Usage
Internet Usage
Internet Usage
Internet Usage
Uses of the Internet
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Email and Mailing Lists
E-mail – allows "mailing electronic" messages
LISTSERVs - special mailing lists allowing exchange of
info between large groups of people
According IDC, on an average day in 2000, 5.1 b
emails are sent in the US and 8.2 b worldwide
Telnet
Connection to remote hosts
FTP and File Sharing
Used to place variety of information online
Originally text only e.g. Kazaa, Napster, Emule
Uses of the Internet …cont’d
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Newsgroup, User group & Bulletin Boards
USENET - system of special interest discussion
groups to which readers can "post" messages
that are distributed to other computers
Newsgroups organized around specific topics
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Website Browsing with World Wide Web
World Wide Web (WWW or the Web) interesting to people because it includes
pictures and sounds.
Uses of the Internet …cont’d
Chatting & SMS (MSN,Yahoo)
Like telephone, Internet allows you to "chat" with
people by participating in online discussion groups
 News and Information Dissemination
Like newspaper, the Internet can give you new
information every day, including world news,
business, sports, travel, entertainment, and ads
 Libraries and Research
Like library, Internet contains information on any
topic you can imagine in many formats, including
books, articles, videos, and music recordings
 Search Engines
There are several search engines including:
Yahoo, Google, Altavista, Infoseek, Lycos, Hotbot…
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Uses of the Internet …cont’d
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Entertainment
Streaming Media (Video/ Radio), Games, Novels
Internet Telephony
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E-commerce (Amazon, Ebay, Walmart)
Advertising, Shopping & Business Processes
Internet Banking/ Auctions/ Lotteries/ Gambling
Customer Care and User Support
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Video Conferencing & Communication
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E-learning, Open and Distance Learning
Professional courses & Degrees
Dangers of the Internet
Internet use catching on faster than any form of
technology ever invented
 Its potential for human benefit is beyond
measure, but it is not without problems:
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Marriages break up over “e-relationships”
Students risk health/grades to spend time online
Child abusers lure kids through the internet
Adults spend fortunes to subscribe pornography
Internet fraud and Cyber crime is here and now
Users have crossed boundary between healthy
use & obsessive preoccupation with the internet
Dangers of the Internet ..cont’d
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Exposure to Inappropriate material
Children, youth and the “tempted”
Hate messages, violence and sexual material,
jokes on physical violence, assaults, aggression,
and exchange involving racial prejudice
Chat rooms and messages on sexual advances
Dangers of the Internet ..cont’d
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Hazards of real life Meetings:
Research in Thailand indicated:
24% of children and 37% of youths had at least
one 'physical' meeting with someone they had
only communicated with online
42% of children said that they would like to
meet their virtual friends at some point
Majority surprised by the identity of the person
and at times the surprise was a nasty shock
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Creation of unhealthy new relationships and
identities
Dangers of the Internet ..cont’d
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Unwanted Distribution of Personal Info
◦ Sale of mailing lists and address information…
◦ Physical address posing danger from molesters
◦ Credit card information
◦ Passwords
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Negative Language development
F2F - face to face,
TNSTAAFL, there’s no such thing as a free lunch
FYI - for your information
IMHO - In my humble/honest opinion,
TTFN Ta Ta for now, BRB - be right back
BTW - by the way
Dangers of the Internet ..cont’d
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Fraud and Identity Theft
"Credit identity theft“ means theft of consumer's
personal and credit information which a thief uses
to gain access to victim's credit & bank accounts
Personal identification information that is available
on the Internet can be accessed by anyone and
misused to obtain credit in the victim's name
Dangers of the Internet ..cont’d
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Adverts, Spam, Junk and unsolicited Mail
The average user now receives 81 e-mails each
day, and nearly one quarter of them are spam
"As long as people buy the products, I'll keep
sending mail," says Ron Scelon, a self-described
"spammer," he runs Scelon Marketing, which sends
up to 100 million unsolicited e-mails a day
Dangers of the Internet ..cont’d
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Cyber-Terrorism (Hacking)
Hacking is simply, asking a lot of questions and
refusing to stop asking
They don't tell you to shut up for asking
questions / inputting commands over and over
Hacking is unauthorized use of computer and
network resources
Threats to shutdown Internet!
Dangers of the Internet ..cont’d
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Internet as a Health hazard
Some 300K of Taiwan's 6 m Internet users may
be sufferers of a condition known as Internet
Addiction Disorder (IAD)
IAD is defined as a psycho-physiological disorder
involving tolerance of long online hours,
withdrawal symptoms (anxiety and depression)
and a failure to regulate daily Internet use,
resulting in impairment of relationships
5% of users are "possible sufferers" of IAD
Dangers of the Internet ..cont’d
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Computer Viruses, Worms & Trojans
The issue of hoaxes
◦ Hook, Threat and Request
◦ "send this to everyone you know"
Necessary condition to be considered a virus is:
◦ Capability to produce copies of itself
◦ Incorporate itself into computer networks
and/or files, system areas of computers, and
other executable objects
◦ Copies maintain capability to spread further
Suggested Solutions
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Educating adults and children about Internet
Role of the Church… who pastors the Pastor?
Absentee “parent”
Legal Approach: Laws & the Web Police
Economic Controls: Make expensive to send email
Advert blocking, Anti-Spam & Junk buster s/w
Filters that block access to sites or chat rooms
Refuse connections from known offenders
Use of secure browser that encrypts information