The Internet: A Network of Networks

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The Internet A Network of Networks

• The Internet is an interconnected network of
  thousands of networks linking academic, research,
  government, and commercial institutions.

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Internet Users

• Increasing Exponentially
• How many online users
• Who are the users
• Government, Education, Research
• Commercial companies
• Organizations
• Individuals

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Internet Communications

• Originally for
• Email
• FTP
• Telnet

• Now with WWW
• Instant Messaging
• Voice over Internet (VoIP)
• Weblogs
• Podcasts
• Webcasts and Wikis
• Chat Rooms
• Newsgroups

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Instant Messaging

• Real-time text-based conversations
• Set up a list of contacts
• Buddy list
• Contacts must be online
• IM software detects presence
• Example AOL Instant Messenger

5
Voice over Internet Protocol

• VoIP - The Internet as a means to place phone
  calls
• Uses technology similar to e-mail to send voice
  data digitally
• Requires
• a microphone
• an Internet connection
• A VoIP provider
• Services differ
• Free services require an account on both ends
• Paid services connect phone to computer
• Cable and DSL providers offer phone through
  broadband
• WiFi IP phones call through Internet hotspots and
  wireless networks

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Weblogs (blogs)

• Known as blogs
• Available to the public
• Simple to create, read, and manage
• Entries listed on a single page
• Most recent entry at the top

• Searchable
• Some are personal
• Many are focused on a topic

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Podcasts

• Video blog (vlog) entries are video clips
• Podcasts compressed audio/video files
  distributed on the Internet
• RSS (Really Simple Syndication) technology allows
  constant updates for subscribers
• Podcasts are all over the Web
• Requires aggregator software to gather podcasts
• Requires media player software to play them
• Simple to create and attach RSS files

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Webcasts and Wikis

• Webcasts broadcast audio/visual files but are not
  updated
• use streaming media
• A wiki is a Web site that allows anyone to change
  its content
• Wikis provide an excellent source for
  collaborative writing
• Unlike blogs, wikis can be edited for a common
  opinion

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E-mail

• Electronic mail
• Primary means of communication
• E-mail accounts
• Client-based
• Web-based
• Spam
• Prevention

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Chat Rooms

• Real-time text-based conversations
• Rooms focus on specific topics or interests
• Identity protection
• Username

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Newsgroups

• Online discussion forums
• Post and reply to messages

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Social Networking

• MySpace.com, Facebook.com
• Members share common interests
• Members communicate by voice, chat, instant
  message, video, and blogs
• Members create personalized profiles
• Growth has been explosive
• Risks must be recognized and reduced

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Web Entertainment

• Multimedia
• Involves forms of media and text
• Graphics
• Audio
• Video
• Streaming audio and video
• Plug-in

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Conducting Business Over the Internet

• E-Commerce
• Electronic commerce
• Business-to-consumer (B2C)
• Business-to-business (B2B)
• Consumer-to-consumer (C2C)
• Secure transactions

B2B E-commerce
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Internet Growth

• June 1999 there were 8.1 Million registered
  Domain Names. Currently 2.6 BILLION
• Internet2 (next generation) will reduce the load
  in the current internet network
• Will have a higher bandwidth (40-100gps)
• Small number of Users
• currently about 208 Universities,
• 67 Corporations
• Current member of NCREN
• NC Research and Education Network

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Over 206 Internet 2 Members was 9Gbps now
100Gbps since 2007
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Internet Backbones

• Backbones, high-capacity transmission lines, can
  be regional, continental, or transcontinental
• The internet 2 backbone was upgraded in 2007 to
  100 GB/sec .

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Circuit SwitchingContinuous Connection

• A continuous connection or circuit is forged
  between transmitter and receiver
• Ordinary telephone connections are made by
  circuit switching

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Packet SwitchingConnectionless

• In packet switching, the message is broken up
  into separate data packets each addressed to the
  destination
• Packets are transmitted over any available route
  to the destination, where the receiving node
  reassembles the message

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Switching and Routing Techniques

• Packet switching
• Outgoing messages are divided into fixed-size
  data units called packets
• Packets are numbered and addressed to the
  receiving computer
• Routers examine the packets and send them to
  their destination (not always on the route)

• Circuit switching
• Networks create an end-to-end circuit between the
  sending and receiving computers (like a telephone
  connection)
• Electronic switches establish and maintain the
  connection

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Advantages and Disadvantages of Circuit and
Packet Switching
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Online Annoyances

• Spam electronic junk mail
• Pop-ups intrusive advertising
• Cookies tracking users browsing habits
• Spyware programs that collect data from a
  users computer
• Malware - software that has a malicious intent
• Phishing and Hoaxes Ruses to fool and maybe
  steal from users

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Spam

• Junk e-Mail
• Spam filters
• Antispam practices

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Pop-ups

• Usually advertising
• Pop-up automatically
• Pop-up blockers

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Cookies

• Text files stored on client computers when
  visiting Web sites
• Used on return visits to Web sites
• Unique ID number
• Personal information remembered
• Privacy risk
• Selling information

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Global Unique Identifiers (GUIDs)

• A GUID is a unique identification number
  generated by hardware or a program
• It is used to send user information back to the
  site that created it

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Spyware

• Added as a program piggybacked with a requested
  program
• Gathers information, usually about surfing habits
• Antivirus software doesnt detect it
• Spyware removal programs are required

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Malware

• Software that has a malicious intent
• Spyware is a form of malware
• Other forms are viruses, worms, and Trojan horses
• Designed to render a computer useless or
  penetrate it completely

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Phishing and Hoaxes

• Phishing is a phony communication
• Attempts to scam someone into sending vital
  information
• Hoaxes are attempts to scam people into sending
  money, or join a chain letter

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Phishing
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Navigating the Web Web Browsers

• Computer software
• Graphical
• Enables Web navigation
• Popular browsers
• Internet Explorer
• Netscape Navigator
• Camino (Mac OSX)

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Browser Toolbars
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Web Sites

• Web site
• Collection of related Web pages
• First page known as Home or Index page
• Web page
• HTML document
• Text and graphics
• Unique address
• Hyperlinks

Home page
Related pages
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Fetching OpeningWeb Pages

• Web browsers ask for pages by their URLs
• Uniform Resource Locator

http//www.cs.unca.edu/massey/csci107/schedule.ht
ml
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Current Top-Level Domains

• .aero Members of the air transport industry
• .biz Businesses
• .com Can be used by anyone
• .coop Cooperative associations
• .edu Degree granting institutions
• .gov United States government
• .info Information service providers
• .mil United States military
• .museum Museums
• .name Individuals
• .net Networking organizations
• .org Organizations (often nonprofits)
• .pro Credentialed professionals

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Domain Names

• Domain Names are pseudonyms for IP addresses
• URL may be HTTP//www.google.com
• IP numerical address is 216.239.37.99
• Domain names can be bought if it is available
• Buy/sell domain names if your choice is taken

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Hyperlinks

• Provide access to other Web pages
• Specially coded text or graphics
• Cursor becomes a hand with finger pointing upward

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Favorites and Bookmarks

• List created of favorite Web pages
• Easy method of returning to Web pages
• Internet Explorer uses Favorites
• Netscape uses Bookmarks
• Live Bookmarks use RSS

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Tabbed Browsing

• Found on Firefox and Safari browsers
• Finally in Internet Explorer 7.0
• Multiple pages in same browser window

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Search Engines

• User keys word or phrase in search box
• Spider or Web Crawler program scans Web pages
• Results are indexed and sent to the client

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Searching the Web
Ways to search the Web

• Search engines
• produce a list of pages that match a keyword
• they are built around a database that catalogs
  Web locations based on content
• Directory or Subject Tree
• A hierarchical catalog of Web sites
• Natural Language Search Engines
• Allows users to ask for what they want

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Search Engines Google
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Search Engines Google
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Search Engines

• Search engines help find information when you
  type a query using keywords.

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Subject Directories

• Web pages organized by topics and subtopics

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Search Engines

• Ask questions in a Natural Language Search Engine

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Searching on the Web

• robot-assisted databases
• automated collection of URLs based on keyword
  analyses
• spiders, knowbots examine titles, text, and index
  material for keywords
• Find and save to the database the URL and
  sometimes the other URLs on the same page.

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Searching on the Web

• metasearch engines search other search engines.
• examples Dogpile, Ask Jeeves, Surfwax

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Portals

• Portals are gateways of organized links for
  quick and easy access to a variety of services
  such as e-mail, chat,maps, news, shopping, etc.

• Examples of consumer portals include
• Yahoo!, Excite, Alta Vista, Netscape, WalMart

• Specialized portals target specific industries,
  economic and education sectors
• UNCA, Medical, Construction

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Need for EvaluatingContent on the Web

• lack of review mechanisms
• anonymity of sources
• lack of safeguards for published materials
• timeliness of published materials on the Web
• the shelf life is shorter
• the pressure to publish quickly can backfire
• Much is inappropriate in the opinion of many
  people

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Evaluation Criteria

• accuracy-- (how reliable?) look for and verify
  sources
• authority-- (how reputable?) what are the
  authors qualifications?
• objectivity-- (any biases?) identify motivations
  or agenda of the publishers
• currency(is up-to-date?) when was the page
  posted? modified?
• coverage-- (depth? breadth?) consider source and
  purposes