Transcript Why Study Computers?

Review of Basic Concepts:
CH 4-5
 Telecommunications
 The Internet
 The Web
Please discontinue use of cell
phone and turn off ringer
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Telecommunictions &
Computer Networking
 Networking Hardware,
Software, and Protocols
 Network Types
 Wireless Networks
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Telecommunications –
Electronic Communications
 Voice and data telecommunications
 Analog vs. Digital
 Components
 Hardware
 Software
 Protocols: rules of engagement
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Networking Media
Twisted Pair
Cable
 Coaxial Cable
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Fiber Optic
Cable
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Radio Frequency
4
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Signal Frequency
 Frequency: the speed at which a signal
changes from high to low.
 Bandwidth: the range of signal frequencies
that can be sent over a given medium at the
same time.
 Often expressed as bits per second
 Broadband: faster than 200Kbps
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Networking Devices
 Modem: modulates and
demodulates signals from one form
to another.
 Network Adapter: Expansion card,
or external device installed on a
computing device used to connect
to a network.
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Networking Devices
 Network Control Devices:
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Hub
Switch
Repeater
Bridge
Gateway
Router
Wireless Access Point
Firewall
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Wireless Fidelity (Wi-Fi)
 Wi-Fi: devices that communicate wirelessly
using the 802.11x protocol.
• 250-1,000 ft range
• 802.11b 11 Mbps
• 802.11g 54 Mbps
• www.boingo.com
Access
Point
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Bluetooth
 Bluetooth: Wireless technology that enables
a wide variety of digital devices to
communicate directly.
• 33 ft range
• 1 Mbps
• www.bluetooth.com
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Infrared (IRDA)
 Infrared technology utilizes infrared rays to
send data over a short distance wirelessly.
• 14 ft range
• Narrow-angle cone (30o)
• Line-of-sight
• 4-16 Mbps
• www.mzoop.com
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Wireless Comparison
Wi-fi
Access
point
centered
LAN
Omnidirection
Through
250 ft
obstructions range
indoors
54 Mbps
Bluetooth Point-topoint
Omnidirection
Through
33 ft
obstructions
1 Mbps
Narrowangle
Line-of-sight 14 ft
4 Mbps
Infrared
Point-topoint
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Network Types
 Local Area Network (LAN)
 Connects computer systems and devices within
a common geographic area
 Wide Area Network (WAN)
 Connects LANs between cities, cross country,
and around the world using microwave and
satellite transmission or telephone lines.
 Global Area Network (GAN)
 An International network
 An internet
 A network consisting of connected smaller
networks
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Network Types
 Personal Area Network (PAN)
 The interconnection of personal information
technology devices within the range of an
individual - typically using Bluetooth Tech.
The original PAN was
designed by Thomas
Zimmerman and allowed
users to pass digital
electronic information
through touch, by transferring
information from one
person’s device to another’s,
running a subtly current
through the body.
The Body Bus?
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Installing Home Wi-fi
 Requirements
 High-speed Internet
 Cable Modem or DSL
Modem (provided be
ISP)
 Wireless Access
Point/Router
 Wireless adapters for
each device.
 Additional Access Points
as needed.
http://www.linksys.com/
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Wireless Access
Point / Router
Cable Modem
To Cable Co.
The Internet
 The Internet
 The Web
 Applications
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What is the Internet?
Visualization of the Internet’s topology from
http://www.cybergeography.org/atlas/topology.html
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The Internet
 The Internet is the world’s largest public
computer network, a network of networks
that provides a vast array of services to
individuals, businesses, and organizations
around the world.
 The Internet is a combination of hardware,
software, and protocols.
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Internet Hardware
 The Internet backbone consists of the
main pathways and connections of the
Internet owned primarily by telecom
companies.
Verizon’s/MCI’s UUNet carries 28% of Internet traffic
http://en.wikipedia.org/wiki/Internet_backbone
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Internet Hardware
 Network Service Providers
 Major telecom
companies that provide
the Internet backbone.
Network Service
Providers
27.9%
Verizon/MCI/UUNET
10.0%
AT&T
6.5%
Sprint
6.3%
Genuity (level 3)
4.1%
PSINet
3.5%
Cable & Wireless
2.8%
XO Communications
2.6%
Verio
1.5%
Qwest
http://navigators.com/isp.html
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Internet Hardware
 Points of Presence (POPs)
 Facilities provided by Network Service Providers
that allow users to connect to the Internet
backbone.
 Internet Service Providers
 Companies that provide users with access to the
Internet.
 Dial-up vs. DSS vs. Cell vs. DSL vs. Cable
Top 22 ISP’s:
http://www.isp-planet.com/research/rankings/usa.html
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Internet Hardware
 Routers: computing
devices that manage
network traffic by
evaluating data packets
and routing them to their
destination.
http://computer.howstuffworks.com/router1.htm
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7’
The Cisco CRS-1 router is
controlled by a unique selfhealing and self-defending
operating system designed for
always-on operation while
scaling system capacity up to 92
Tbps. Routers such as this one
manage traffic on the Internet
Backbone.
Packet Switching
An email message
Dear Joan,
Hi! How’s it goin’? Just finished midterms, and it looks like I
might graduate this semester after all! :-) My computer
teacher is really great and I guess that I learned more than
I thought in those wonderful lectures that I had previously
written you about….
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Packet Switching
Broken into packets
Dear Joan,
Hi! How’s it goin’? Just finished midterms, and it
looks like I might graduate this semester after all! :-) My
computer teacher is really great and I guess that I
learned more than I thought in those wonderful lectures
that I had previously written you about….
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Packet Switching
Packet headers added
Dear Joan,
Hi! How’s it goin’? Just finished midterms, and it
Message 3761HZA Date May 1
Packet 1 of 3
From [email protected]
To [email protected]
looks like I might graduate this semester
after all! :-) My computer teacher is really
great and I guess that I
Message 3761HZA Date May 1
Packet 2 of 3
From [email protected]
To [email protected]
learned more than I thought in those
wonderful lectures that I had previously
written you about….
Message 3761HZA Date May 1
Packet 3 of 3
From [email protected]
To [email protected]
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Packet Switching
Each packet sent individually over the network
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Packet Switched Network
email
email
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Circuit Switched Network
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Packet Switching
 Packet switching is much more efficient
than circuit switching.
Technology: Networking/Telecoms
Wednesday 28 May 2003
Sprint moves to packet-switch network
Sprint is to change its entire circuit-switched telephone network to packet
technology in an attempt to keep up with customer demand for capacity.
Sprint's eight million lines will be moved over to the packet-based asynchronous
transfer mode (ATM) system, allowing voice, video and data to be broken down into
small digital blocks and sent, in effect, simultaneously.This allows the network to be
used more efficiently, and will also allow new multimedia services, Sprint said.
Sprint is the first major telecoms company to move all of its local, tandem and longdistance networks over to packet technology, according to Nortel
Networks spokeswoman Ann Fuller.
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Internet Protocols
 Protocols are rules that govern how data is
transmitted and received.
 They govern all Network and Internet
communications:
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The Internet
The Web
Email
Instant Messaging
Etc.
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Ports are numeric addresses
assigned to specific network
services, and used in packet
headers to direct data packets to
the appropriate service. See
http://en.wikipedia.org/wiki/List_of_
TCP_and_UDP_port_numbers
Internet Protocols
 TCP/IP
 Transaction Control Protocol (TCP): Divides data into
packets for transmission, and reassembles data from
packets upon delivery.
 Internet Protocol (IP): Controls the delivery of packets
between IP addresses.
 IP Address
 a 32-bit number that identifies each sender or receiver of
information that is sent in packets across the Internet.
 10000000.11111111.10110101.00010111
 128.255.181.29
 www.fsu.edu
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Network Architectures
 Client/Server
 Peer-to-Peer
Original Napster vs. Kazaa
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The Web
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The Web
 The World Wide Web is an Internetbased service that provides convenient
access to information through
hyperlinks.
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Web Protocols & Standards
 HTTP: Hypertext Transfer Protocol defines
and controls communication between Web
server and client (Web browser).
 URL: Uniform Resource Locator is the
fancy name for a Web address.
http://www.cs.fsu.edu/~baldauf/presentations/swt/2/index.html
Domain name
http://www.icann.org/
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Web Protocols & Standards
 HTML: Hypertext Markup Language is the
formatting language used to define the
appearance of Web pages.
 Try View Source in IE
 XML: New and popular standard for
describing and classifying data in Web
pages and other Web services.
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Web-Authoring Software
 Web Authoring Software allows you to
create HTML documents using wordprocessor-like software
Macromedia’s
Dreamweaver
software allows
you to design
Webpages and
Websites using a
WYSIWYG
interface.
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Internet and Web
Applications
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The Internet & Web
Communications
The Web
E-commerce
Information
Distribution
The Internet
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Communication and
Collaboration
Effectiveness
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Face to Face
Video + Voice
Voice Only
Text Only
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Communication and
Collaboration
 Synchronous Communication takes place in
real time.
 Phone conversation
 Instant Messaging
 Asynchronous Communication allows
participants to leave messages to be
accessed whenever.
 Voice mail
 Email
 SMS Texting
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3. Phone (voice)
4. Instant messaging/Chat
5. Voice mail
6. Email
7. SMS Texting
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Convenience
Asynchronous
1. Face-to-face
2. Video conferencing
Effectiveness
Synchronous
Communication and
Collaboration
Voice over IP (VoIP)
 Technology that
enables network
managers to route
phone calls over
the same network
they use for data.
Future of Phones: http://newsroom.cisco.com/dlls/video_audio_archive/?all
Also see Video Telephony
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Residential VoIP
• Residential VoIP, also called Internet
Phone, Broadband Phone
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Place phone calls over your broadband
Internet connection.
http://www.vonage.com
http://www.voipchoices.com/
http://www.fcc.gov/voip/
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News and Information
 On-line news services allow you to drilldown into the story to get background
information and details.
Webcasting uses the Web
to deliver news video
footage.
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Education and Training
 Life-long learning is your future…
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• 1,850 IT and
desktop e-Learning
courses
• 1,300 business and
professional
development eLearning courses
• 2,000 up to date,
searchable, IT,
Desktop and
Business Books
from Safari
• 250 instructor and
student manuals for
ILT training
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E-commerce
 E-commerce has opened up new
opportunities in buying and selling.
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Travel
 The Web has transformed the travel
industry.
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Employment and Careers
 The Web assists us in researching
career possibilities:
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Selecting a career
Researching companies
Networking with colleagues
Searching want ads
Creating Resumes & Professional
Websites
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Multimedia & Entertainment
 Music
 Movies
 Games
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Information
Consumers are increasingly reliant
upon online resources to ease and
inform major life events.
 Research on the Web
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Subject Directories, and Search Engines
Issues of reliability
Library Web sites
Research Databases
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Chapter 4 & 5 Questions?
Don’t forget to turn
your phone on!!
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