ACS-1803-052 Introduction to Information Systems

1
ACS-1803-052Introduction to Information Systems

• Instructor Kerry Augustine

Networked Computing Lecture Outline 3
Fundamentals of Information Systems, Sixth
Edition Ralph Stair, George Reynolds
2
Networked Computing

• Uses telecommunications technology
• See p. 160 why learn about telecommunications
  and networks

3
Overview of telecommunications

• P. 161
• Refers to the electronic transmission of signals
  for communications, by such means as telephone,
  radio and television
• Lessens barriers of time and distance

4
An Overview of Telecommunications (continued)
5
General Model of Telecommunications

• See p. 161
• 1. Sending unit (computer)
• 2. modem 3 converts signal
• 4. telecomm medium
• 5. modem 6 receives signal
• 7. receiving unit (computer)

6
Network Hardware and Software (Hardware)
Modem (Modulator/Demodulator) Enables computers
to connect and transmit data over phone lines by
converting the sending computers digital signals
to analog and back again for the receiving
computer
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Speed of Transmission

• Measures in bits per second (bps)
• Thousands of bite per second - Kbps
• Millions - Mbps
• Billions - Gbps
• Broadband telecommunication rate of exchange of
  data gt 1.5 Mbps

8
Transmission Media

• Physical pathways between network members
• Computers send bits to each other ( / -)
• Different media chosen to make up pathways
• Cables twisted pair, coaxial, fibre optic
• Wireless infrared line of sight, high frequency
  radio, microwave 162-3
• Read WiFi p. 164

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Networking Fundamentals Transmission Media
Transmission Media The physical pathway to send
data and information between two or more entities
on the network. Characteristics of the media
include the following
Bandwidth Is the transmission capacity of a
communications channel or computer, measured in
megabits per second (Mbps) (amount of binary data
transmitted per second)
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Networking Fundamentals Transmission Media
(continued)
Twisted Pair (TP) Two or more pairs of insulated
copper wires twisted together and may be shielded
(STP) or unshielded (UTP). It is the lowest
capacity of the cable options
Coaxial (COAX) Contains a solid inner copper
conductor surrounded by insulation and outer
braided copper or foil shield. It is higher
capacity than twisted pair
Fiber-Optic Made of light-conducting glass or
plastic core, surrounded by more glass, called
cladding, and a tough outer sheath. It is high
capacity and used in high speed backbones
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Networking Fundamentals Transmission Media
(continued)
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Wireless media (p. 166)

• Infrared Line of Site (LOS) like TV remote
  control
• High-frequency radio needs antenna towers used
  in pagers, cellular phones, police / taxi radio
  in cars
• Microwave long distances
• Terrestrial antennas every e.g., 30 miles
• Satellite signals from antennas on Earth to
  Satellites in space and back down
• See p. 165

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Networking Fundamentals Media (Wireless)
Cellular Phone A two-way wireless communication
that assigns unique frequencies to calls and can
transmit in analog or digital
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Communications Media (continued)

• 3G wireless communications
• Supports wireless voice and broadband speed data
  communications in a mobile environment
• 4G wireless communications
• 4G will also provide increased data transmission
  rates in the 2040 Mbps range
• Worldwide interoperability for microwave access
  (WiMAX)
• Operates like Wi-Fi, only over greater distances
  and at faster transmission speeds

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Telecommunications Hardware

• Smartphones
• Combine the functionality of a mobile phone,
  camera, Web browser, e-mail tool, MP3 player, and
  other devices
• Have their own software operating systems
• Applications are developed by
• The manufacturers of the handheld device
• The operators of the communications network on
  which they operate
• Third-party software developers

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Networking Fundamentals Media (Wireless)
Wireless LANs or Wireless Fidelity (Wi-Fi) Based
on a standard called 802.11, this technology
enables multiple computers to share Internet
access, files, and peripheral devices
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Networking Fundamentals Media (Microwave)
Microwave A high frequency radio signal that is
sent through the air using either terrestrial
(earth-based) or satellite systems
Terrestrial Microwave A line-of-site technology
(unobstructed) used to cross inaccessible terrain
or to connect buildings where cable installation
would be expensive. Attenuation is low over
short distance but higher over longer distances,
and high winds, heavy rain, EMI and eavesdropping
are also problems
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Networking Fundamentals Media (Microwave)
Satellite Microwave A line-of-site technology
that uses relay stations to transfer signals
between antennae located on earth and a satellite
orbiting the earth. It can be used to access very
remote locations and, like a terrestrial
microwave, attenuation, EMI and eavesdropping are
also problems
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Computer Networks
Centralized Computing (1970s) The centralized
computing model utilizes a central computer
(mainframe) connected to terminals with all
processing being done on the central computer
Distributed Computing (1980s) The use of small
computers networked together allowing users to
perform a subset of tasks that in aggregate are
equal to that of a centralized computer while
also being able to share information between
those computers
Collaborative Computing (1990s) A synergistic
form of distributed computing in which two or
more networked computers are used to accomplish a
common processing task where they are not only
sharing data but also sharing processing
responsibilities
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Types of Computing
Centralized Computing
Distributed Computing
Collaborative Computing
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Centralized Computing

• One central computer (e.g. mainframe) with dumb
  terminals
• All processing occurs in one central mainframe
• Not a true network as no sharing of information
  and capabilities

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Distributed Processing

• Centralized processing
• All processing occurs in a single location or
  facility
• Decentralized processing
• Processing devices are placed at various remote
  locations
• Distributed processing
• Processing devices are placed at remote locations
  but are connected to each other via a network

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Client/Server Systems

• Client/server architecture
• Multiple computer platforms are dedicated to
  special functions
• Server
• Distributes programs and data to the other
  computers (clients) on the network as they
  request them

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Telecommunications Software

• Network operating system (NOS)
• Systems software that controls the computer
  systems and devices on a network
• Network management software
• Protects software from being copied, modified, or
  downloaded illegally
• Locates telecommunications errors and potential
  network problems

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Types of Networks

• Networks
• Most networks utilize a combination of computing
  models that have evolved over time and are
  connected by one or more of the following network
  types
• Private Branch Exchange (PBX)
• Local Area Network (LAN)
• Wide Area Network (WAN)
• Global Networks
• Enterprise Network
• Value-added Network (VAN)
• Metropolitan Network (MAN)
• Personal Area Network (PAN)

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Networked Computing

• Most common arrangement in business computing
• See telecommunications overview p 161.
• Make brief notes
• Types of networks (p. 169-170)

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Local Area Network

• Computer network in a small area
• Private cabling (twisted pair or coaxial)
• Some may be wireless
• Usually has a file server (captain)

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Local Area Network
Local Area Network (LAN) A computer network that
spans a relatively small area allowing all
computer users to connect with each other to
share information and peripheral devices (e.g.,
printers)
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•  Common Network Components
•  
• what will we need in order to set up a computer
  network (LAN)?
• - server main computer in a network
• - workstations other computers in the network
• - Network Interface Cards (NICs)
• - private cabling
• - Network Operating System e.g. Novell
  Netware (Windows NT, 2000,2003, 2008)
• p 171

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Why Connect?

• Share data (which resides on server)
• Share software
• Share peripherals (printer)
• Computers (workstations) can communicate with
  each other and send files
• files services, print services, message services,
  application services

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Types of Networks Wide Area Networks (WAN)
Wide Area Networks (WANs) A computer network that
spans a relatively large area and is typically
used to connect two or more LANs using different
kinds of hardware and transmission media to cover
large distances efficiently
Global A WAN that spans multiple countries and
may include the networks of several organizations
(e.g. the Internet)
Value-added Network (VAN) A medium-speed,
third-party-managed network that is economical as
it is shared by multiple customer organizations
that lease lines rather than investing in
dedicated network equipment
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Types of Networks Wide Area Networks (WAN)
Enterprise Network MAN
Enterprise A WAN that is the result of connecting
the disparate networks of a single organization
Metropolitan Area (MAN) A WAN network of limited
geographic scope, typically in a city-wide area
that combines both LAN and high-speed fiber-optic
technologies
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Types of Networks Personal Area Network (PAN)
Personal Area Network (PAN) An emerging
technology that uses wireless communication to
exchange data between computing devices using
short-range radio communication (Bluetooth),
typically within an area of ten meters
Bluetooth Is the enabling technology of the
Personal Area Network and is a specification for
personal networking of desktop computers, mobile
phones, pagers, portable stereos, and other
handheld devices developed by its founders
Ericsson, IBM, Intel, Nokia, and Toshiba
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Server and clients (p. 171)

• The Server is the captain of the network
• It has more advanced CPU, more memory, more disk
  storage
• It serves data files, software, access to
  peripherals (printers) can store your data on
  server disk
• Runs a network operating system (NOS)
• Clients are individual members of network

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Networking Fundamentals Servers and Clients
Network A network consists of three separate
components servers, clients and peers
Server Any computer on a network that makes
access to files, printing, communication, and
other services available to users on the network
Client Any computer, such as a users workstation
or a PC on the network, or software application
such as word processing program that uses
services provided by the server. A client only
requests service and usually has only one user
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Networking Fundamentals Peers
Peer A computer that may both request and provide
services
Peer-to-Peer Networks (P2P) Enables any computer
or device on the network to provide or request
services with all peers having equivalent
capabilities and responsibilities (e.g., Napster)
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Networking Fundamentals - Network Services
Network Services The capabilities that networked
computers share through their multiple
combinations of hardware and software
File Services (a) The capabilities that networked
computers share through their multiple
combinations of hardware and software
Print Services (b) The capabilities used to
control and manage users access to network
printers, plotters, fax equipment, etc.
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Networking Fundamentals - Network Services
Message Services (c) The capabilities that
include storing, accessing, and delivering of
text, binary, graphic, digitized video and audio
data
Application Services (d) The capabilities that
run software for network clients and enable
computers to share processing power
Network Operating System (NOS) Is software that
controls the network enabling computers to
communicate by enabling network services
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Network Topologies

• In what shape are computers connected to each
  other?
• Common
• Star, ring, bus

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Network Hardware and Software (Network Topologies)
Network Topologies Refers to the shape of a
network and comes in three types
Star Network The network is configured in the
shape of a star with all nodes or workstations
connected to a central hub, or concentrator,
through which all messages pass
Ring Network The network is configured in the
shape of a circle with each node connecting to
the next node. Messages travel around the circle
in one direction. Each node examines the message
and uses it or regenerates it and passes it to
the next node
Bus Network The network is configured in the
shape of an open-ended line with all nodes or
workstations connected to the bus individually.
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Network Hardware and Software (Network Topologies)
Star Network
Bus Network
Ring Network
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Network Protocols

• Protocol set of rules on HOW to do something
• Here agreed upon formats for transmitting data
  between connected computers
• How to arrange data packets, how to signal end of
  message, how to specify destination address etc.

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The Internet

• The largest, network of networks
• This will be the next topic, see p. 172

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THE INTERNET

• This will be the next topic, see p. 172
• Large, worldwide collection of networks that use
  a common protocol to communicate with each other
• The largest, network of networks

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History of the Internet

• ARPANET (Advanced Research Project Agency
  Network)
• Created in the 1960s by DARPA (Defense Advance
  Research Projects Agency)
• Used by government and universities as a means to
  communicate for research purposes
• NSFNET (National Science Foundation Network)
• Created in 1986 by the National Science
  Foundation for connecting research institutions
• Connected to ARPANET and many others (BITNET,
  CSNET, etc) to become a major component of the
  Internet
• Internet Support
• Ongoing support comes from many universities,
  federal and state governments, and national
  international research institutions and industry

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How the Internet Works Connecting to the
Internet

• Modem (stands for Modulate/Demodulate)
• A modem converts signals back and forth from
  digital to analog for transmission and receipt
  between computers
• A computer requires a modem to get access to the
  Internet

• Internet Service Provider (ISP) (See p. 175
  177)
• These companies provides access to the Internet
  for a fee (i.e. MTS, Shaw)
• A computer is connected to an ISP through a modem
  to allow Internet access

• Network Access Points (NAPs)
• NAPs connect ISPs together
• They serve as Internet access points for the ISPs
  and serve as exchange points for Internet traffic

• Internet Backbone
• Collection of main network connections and
  telecommunications lines that make up the Internet

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How the Internet Works Shows the Internet
Backbone
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Packet Switching

• Internet uses packet switching to enable users to
  transmit across it concurrently
• What is to be sent down the network is sliced
  up into packets
• Each packet has header with source and
  destination address
• Each computer attached to a network has a unique
  network address

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How the Internet Works TCP/IP Routers
TCP/IP Approach

• TCP Transmission Control Protocol
• Breaks information into small chucks called data
  packets
• Manages the transfer of the packets from computer
  to computer
• Reassembles data packets into a message at the
  destination

• IP Internet Protocol
• Controls how data packets are formed
• Addresses each packet with the source and
  destination address
• A data packet conforming to the IP spec is called
  an IP datagram

• Routers (See p. 174)
• Connect one network to another
• Identify each device on a network as unique using
  IP protocol
• Serve as the Traffic Cop directing packets to
  their destination

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How the Internet Works Sending a Message from
Computer A to D
2
(Router) Reads IP Address of packet,
routes message to Network 2 and Computer D
3
(Computer D) TCP - Checks for missing
packets, reassembles message, discards
duplicate packets
1
(Computer A) TCP - Breaks message into
data packets IP - Adds address of destination
Computer D
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Internet Transmission Media

• Plain Old Telephone (POTS) slow
• DSL Digital Subscriber Line
• Uses telephone line in a special way to fit more
  data no standard modem needed
• TV cable needs cable modems faster
• T1, T3 lines dedicated digital transmission
  lines over long distances
• Satellite connections

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Popular Uses of Internet

• Telnet use remote CPU
• File Transfer Protocol (FTP) download file from
  remote computer
• Internet telephone calls
• E-mail
• Chat messengers
• World Wide Web

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How the Internet Works Web Addresses Domains

• Domain
• Identifies the Website (host)
• Comes in many suffixes such as
• .edu (educational institutions)
• .org (organizations non-profit)
• .mil (military)
• .net (network organizations)
• Example microsoft.com

• IP Address
• Each domain is associated with one or more IP
  addresses
• Format a 32-bit address written as 4 numbers
  (from 0-255) separated by periods
• Example 1.160.10.240

• (URL) Uniform Resource Locator
• Identifies particular Web pages within a domain
• Example http//www.microsoft.com/security/defaul
  t.mspx

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How the Internet Works Managing the Internet

• Internet Registry
• Central repository of all Internet-related
  information
• Provides central allocation of all network system
  identifiers
• Managed by Internet Assigned Numbers Authority
  (IANA)

• Domain Name System (DNS)
• Maintained by the Internet Registry
• Used to associates hosts or domains with IP
  addresses
• Root DNS database is replicated across the
  Internet

• InterNic Registration Service
• Assigns Internet Domains and IP addresses
• Internet Corp. for Assigned Names and Number
  (ICANN) has responsibility for managing IP
  addresses, domain names, and root server system
  management

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World Wide Web

• Hypertext
• A Web page stored on a Web server
• Contains information and links to other related
  information (hyperlinks)
• HTML (Hypertext Markup Language)
• A standard method used to specify the format of
  Web pages
• Uses codes/tags which stipulate how the content
  should appear to the user
• Web Browser
• A software program used to locate and display Web
  pages
• Includes text, graphics, and multimedia content

Web Browser
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World Wide Web

• HTTP (Hypertext Transfer Protocol)
• A protocol used to process user requests for
  displaying Web pages from a Web server
• Web Servers
• A special computer that is specifically designed
  to store and serve up Web pages
• This machine contains special hardware and
  software to perform its many specialized functions

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World Wide Web - Architecture
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World Wide Web p. 180

• Web servers dish out web pages which are read and
  displayed by web browsers
• Web page consists of text, graphics, and
  hyperlinks that lead to another page this is
  hypertext
• Hypertext Markup Language (HTML) is the language
  to define web pages p. 181
• Browsers read HTML and render a page
• See also XML p. 182-3

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A Website

• Collection of interlinked web pages created by
  the same author(s) for common purpose
• Respond to requests over the Internet from
  browsers according to the hypertext transfer
  protocol (http)
• URL (Uniform Resource Locator)
• Each site has a URL address
• http//www.uwinnipeg,ca

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Web addresses

• Website http//www.xxx.yy
• Page on that sitehttp//www.xxx.yy/zz
• Domain name xxx.yy
• Prefix xxx e.g. uwinnipeg
• Suffix yy e.g. .com business
• .org nonprofit organization
• .ca - Canada

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 Internet E-MAIL address   john_at_uwinnipeg.ca e
-mail address has _at_ symbol user name _at_ domain
name   Domain names (general areas)   .com
commercial organization .edu educational
organization .gov government organization .ca
Canada .us U.S. .hk Hong Kong
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IP Addresses

• Each domain name
• uwinnipeg.ca
• is associated with an IP Address
• 32-bit numeric address
• written as 4 numbers separated by periods
• Domain name is translated to IP Address by a
  special server on the Internet
• eg. 1.160.10.240

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•  
• Additional details regarding the Web
• Types of web sites
• Static collection of static documents created in
  HTML and tied together with links
• Static with forms 90 is pure document delivery,
  but also has fill-in forms to collect information
  from the user

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Dynamic Data Access via a Web page, users can
search a catalogue or perform queries on the
contents of a database, e.g. University Course
RegistrationWeb-based Software Applications
facilitate business processes beyond voiding
information have a business information system
on a Web-site, e.g., inventory tracking, sales
force automation
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Overview of a Web Session 1. User, with
browser software, requests a document from a
remote Web server on the Internet - enters
desired address as Uniform Resource Locator
(URL) e.g., http//www.irwin.com - URL
specifies where something is, not what it
is 2. Actual address is determined from a domain
name server (computer) on the Internet
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• Once the machine has been located, a request can
  be sent to the server (discussion between the Web
  browser and the Web server is handled by HTTP
  (hypertext transfer protocol - defines how a
  client must ask for data (pages) from the server
  and how the server responds when it returns what
  was asked for)
• HTTP does not specify how the data is
  transferred, that is up to TCP/IP, at a lower
  level

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• Server attempts to process request (is it valid?)
• - it may send back HTML 'data' (a page)
• - server machines often run the Unix or Windows
  NT OR 2008 operating systems
• - they send data from disk onto the network it
  uses Web Server software, such as Apache

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• The browser, on the client, reads what has been
  sent to it, identifies it as an HTML document,
  and places the page in the browser window
• information moves from the network or modem to
  the client system
• once in the client computer, information goes
  along a bus to the hard disk or into main memory
  (browser might temporarily put info onto disk)
• - it is then processed by the browser software
  only)

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Search Engine p. 189

• Locates on the Web, topics requested
• Returns list of links to web pages
• Examples Google, Yahoo, Alta Vista

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Intranets and Extranets p. 208

• Pre-cursor to e-Business/e-Commerce Systems
• Intranet uses internet technology but is limited
  to one organization
• Extranet is a company Intranet that is also
  connected to several specific external
  organizations (e.g. retailer and its supplier)

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Web portals p. 191

• Portal a web page that combines useful
  information and links and acts as an entry point
  to the Web
• Typically include a search engine, a subject
  directory, daily headlines and other items of
  interest
• E.g. Yahoo Portal, MSN Portal, CNN Portal

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E-Mail p. 192

• Common and useful form of Internet communication
• We-based systems (Hotmail)
• Dedicated e-mail software (Outlook)
• On which computer is your e-mail stored?

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Other interesting applications

• Conferencing p. 194
• Blogging and micro blogging
• Content streaming
• Movies, TV (i.e. Netflix, Internet TV)
• E-books etc.
• Examine these for interest
• How are these influencing business?

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Review

• Summary section, p. 204 -206 and make brief notes

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Internet2

• Mission Internet2 is a not-for-profit
  consortium, led by over 200 US universities,
  developing and deploying advanced network
  applications and technology, accelerating the
  creation of tomorrow's Internet.
• Facilitate and coordinate the development,
  deployment, operation, and technology transfer of
  advanced, network-based applications and network
  services to further US leadership in research and
  higher education and accelerate the availability
  of new services and applications on the Internet.

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Internet2

• Abilene Internet2 backbone network (IP over
  SONET)
• A project of the University Corporation for
  Advanced Internet Development (UCAID) in
  collaboration with various corporate partners
• Link Capacity 13,000 miles of fiber optic cable,
  with over 8,000 miles of interior circuits and
  another 5,000 miles of access circuits
• Operates at OC-192 (9.6 gigabits per second) or
  about 354,000 times faster than a typical
  computer modem.

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Internet2
78
Internet2

• Examples of Applications
• Grid computing
• Telemedicine
• Astronomy
• Tele-immersion
• Music
• Digital Video
• Tele-Operation of Remote Equipment
• Tele-Presence (Cisco)