internet a collection of networks. history arpanet – developed for security of sending in case of...
Post on 18-Dec-2015
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INTERNET
A collection of networks
History
ARPANet – developed for security of sending in case of a nuclear attack
IDEA – the system would not go down
Characteristics
Not all units directly connectedClient/server type of connectivityMakes use of a routerMakes use of a gatewayInformation transmitted by packets
What is the first step in becoming an Internet user?
Subscribe to an ISP
Internet service provider
What am I buying?
Three basic
services
telnet
FTP
Definitions
Telnet – allows communication with remote computers
FTP – file transfer protocol
Email – communication software
You also get 2 protocols:
1. IP
2. TCP
Definitions
IP – internet protocolrefers to type of topologydefines a packet to be 1500 bytesdoes the routing
TCP – transmission control protoTransmission will be through a sequence of
packetsAssembles and disassembles the packets
What else do I get?
Software that is used to explore the Internet
A Browser
Can I get anything else?
Software that adds to the browser (video)
A Plug-In
Additional software – SEARCH ENGINE
Software that builds a database of searchable terms
USES A SPIDER???
Search EnginesVary
InfoSeek – searches newsgroups, FAQs, and email addresses in addition to Web sites
AltaVista – indexes every word on a page
Excite – provides related hints and extra content
Google – results ranked by algorithm based on number of links from other pages
Lycos – numerous search options/a comprehensive directory
HotBot – excels at finding current news/fast
Northern Light – group results by subject, type, source, and language
Two with the Broadest Coverage
Directories
YAHOO
Sites are organized by content category
Metasearch Engines
MetaCrawler
DogpileSoftware that searches the search engines
Boolean Logic
Narrowing the search
Do I have access to the World Wide Web?
You might
And you might not
World Wide Web(WWW)
provides a uniform type of access to all Internet services
A type of GUI (graphical user interface)Characterized by HTML
HTMLhypertext markup language
Hypertext – allows access to other addresses by pointing and clicking on a picture or text
The address is attached through the code of the hypertext format
<A HREF = www.whitehouse.govmain menu </A>
main menu is the text which should be highlighted to access this address
Other HTML symbols
<HTML> </HTML> Goes at the beginning of the document and
at the end to define it as using hypertext protocol
<HEAD> </HEAD>Beginning and end of heading section
<B> </B>Beginning and end of bold text
If a website does not use the World Wide Web, it still has the same services.
Access is no longer through graphics.
Access is now done through a series of menu options.
Important point.
JAVA
A programming that allows permits dynamic Web pages
Allows the following:
dancing icons
sound clips
flashing messages
scrolling banners
applets – programs that provide code for these features
ActiveX controls – Microsoft feature that provides the same features
WARNINGS
Must have a browser that is capable of running these applets
Applets present some security risks.
Disadvantage
Not as user friendly.
Advantage
Downloading time will be less.
Not downloading pictures, colors, etc.
Internet Addresses
URL’s
(uniform resource locators)Each is an IP number.
www.whitehouse.gov
COM
GOV
NET
ORG
MIL
EDU
BIZ
UK
PRO
NAMEAERO
DE
Country designators
COOP
INFO
MUSEUM
COM
GOV
NET
ORG
MIL
EDU
NETWORK of DOMAINSCreates
A MESH TOPOLOGY
WWW.WHITEHOUSE.MAJORDOMO.GOV
DOMAIN
Defines use of hypertext protocol
Individual computer
Subdivision of the individual computer
http://www.fdu.edu/pwagner.html
DOMAIN
Defines use of hypertext protocol
Individual computer
File (web page) to get
Wireless Internet Access
Types of devicesText pagersPDAs – personal digital assistantsPocket computersWeb enabled cellular phones
Wireless Internet Access
Additional hardware/software needed:Account with wireless access service providerCellular modem card or adapter
Problem – limited display area
Wireless Application Protocol – used by providers to convert Web pages to capabilities of hand held devices