Transcript Internet - Laredo Community College

The Internet
(Discovering Computers & Microsoft Office 2010pages 8-10, 44-94, IE2-IE10, Computer Networks
supplement)
One or more stand-alone computers
would not be considered a network
environment – why?
Stand-Alone PC
When computers communicate with each other then you have a network
Communications Protocols determines the rules for
communicating between PCs.
PC gets files from server
Processing
is done
on the Client
PC stores files on server
File Server
PC
PC
Client
Local Area Network
A typical local area network
has clients communicating
with a server
PC
Client
PC
Client
PC
Client
File Server
PC
Client
PC
Client
Local Area Network
You can expand the communications environment by
creating an Internetwork – a LAN connected to a LAN
PC
Client
PC
Client
PC
Client
PC
Client
PC
Client
Router or
Switch
File Server
PC
Client
PC
Client
PC
Client
File Server
PC
Client
InterNetwork
PC
Client
Communications environments
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Wired – cables connect PC clients to each
other or to a server (see exhibit 4-8, page 120 end of
book supplement)
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Twisted pair – telephone wire, narrow
bandwidth
Coaxial – shielded wire, faster than T.P.
Fiber Optic – glass fibers – fastest, broader
bandwidth (more expensive)
Communications Environments
Continued …
– slower, subject to atmospheric
interference
 Wireless
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Microwave – Line of sight transmission, long
range transmission involving relay stations
Satellite – transmission above the earth’s
atmosphere, signals travel in excess of 22,000
miles
WiFi – Wireless fidelity – short distances (25 100 feet)
 Blue
tooth – typically connect wireless peripherals
Topologies – how data travels

Star – Communications occur through the
server, if the server goes down, no more
communications
Topologies continued …
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Ring – data travels in a circular manner, each
workstation dependant on the others, if one
goes down, network is down
Topologies continued …
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Bus – data travels through a central cable, if
cable goes down, no more communication
Network Architectures
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Client Server – Dedicated Server has all
shared resources. PC clients access resources
from the server.
Network Architectures
continued …
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Peer – to – Peer – All workstations play a
dual role of both client and server, sharing
can occur among all PCs. Workstations are
non-dedicated servers
Network terms
Bandwidth – the width of the
communication channel, wider is faster
 Ethernet – most common networking
standard for LANs, to have an Ethernet
network all hardware and software must
adhere to the same standard
 NOS – Network operating system. Servers
use a different O.S. than do PC clients

Networking hardware
(see page 135 end of book supplement)
Network Interface Card – all network
hardware requires one, adds the circuitry
required for communication
 Modem – when using phones lines for
communication
 Switch – connect multiple devices in a
wired network to the server
 Router – to connect multiple networks to
broaden the network

Networking hardware
continued …
Wireless access point – device used to grant
network access to wireless client devices
 Antenna – used to increase the rage of a WiFi network

Network & Sharing Center
(Windows 7)

You can view your network resources and
structure in the Windows 7 Network & Sharing
Center
The Internet involves other components, but in essence is
just a large network
Governmental
Institution (.gov)
PC
Client
PC
Client
To other cities
all over the world
To other cities
all over the world
PC
Client
Chicago
File Server
PC
Client
PC
Client
PC
Client
PC
Client
PC
Client
PC
Client
Communications
Protocol -- TCP/IP
PC
Client
PC
Client
File Server
PC
Client
File Server
Houston
PC
Client
Internet Service
Provider or ISP (.net)
Educational
Institution (.edu)
The Internet
PC
Client
New York
PC
Client
Commercial
Bussiness (.com)
Home
PC
Home
PC
Home
PC
What is the Internet?
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A network of networks interconnected
throughout the world
Typical path to the Internet
Who created it?
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In 1969, the Internet began as a department of
defense project called ARPANet (four computers in
California and Utah) Vincent Cerf & Robert Kahn
are generally acknowledged as the fathers of the
“Internet”.
In 1985 University professors (the original nerds)
expanded the concept into a research tool to share
information with professors across the nation –
This was the creation of the NSF network
WWW

The World Wide Web was created by a
British scientist named Tim Berners-Lee in
the early 1990s. The WWW provides the
GUI for the Internet. Utilization of the
WWW led to the popularity explosion of
the Internet
Internet Hosts

A Host on the Internet is a computer that contains data
that may be accessed by users anywhere in the world

The Internet began with 4 hosts in the 1960’s and today
numbers over 550 million
The Internet “backbone” is comparable to major interstate highways
running throughout the nation. Internet traffic flows through the backbone
Most backbones are maintained by “AT & T”, “SBC”, “MCI”, “Sprint”,
and others. These companies are known as “Network Service Providers”
(NSPs)
What do I need to get on the
Internet?
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A computer, phone, game console, etc.
Internet Connection:
A modem / telephone line (dial-up – slow)
** DSL – Provides high-speed Internet connection
using regular telephone lines
 Fiber to the Premises (FTTP) – uses fiber optic cable to
provide high-speed Internet access to home and
business users
 Fixed Wireless – high speed Internet connection via
radio signals using antennas & towers

What do I need to get on the
Internet, continued …

Satellite – when cable hookup is not available - farthest
range but not as fast as other connections and subject to
interference in the atmosphere
Cable Modem – TV cable line – typical speed 6 – 30
Mbps. Referred to as an “Always On” broadband
connection
Wi-Fi (wireless fidelity) – Uses radio signals to
provide wireless access to computers and devices
Cellular radio network – offers high-speed Internet
connection to devices with built-in compatible
technology
What do I need to get on the
Internet, continued …
ISP
- Internet Service Provider - a company that provides
access to the Internet through their equipment (monthly fee
required – National, regional, or local)
OSP
– Online service provider – provide extra services
for members, example: AOL, MSN

A Browser - software that allows a user to navigate
through the Internet
What Can I Do on the Internet?
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Broadcasting – viewing video teleconferences as well as
listening to radio shows (webcasts). Podcasts are popular
today
Internet Telephony – free “telephone like” conversations
(Voice over IP - VoIP)
Send electronic correspondence (E-mail web or client based)
Advertise
Research information using Gopher (non-graphical) or the
WWW
Converse with other users in “Chat Rooms” / Instant
Messaging (IM) is a variation of the traditional chat
What Can I Do on the Internet,
continued …

E-commerce – Shop on the Internet –
ensure the VeriSign seal displays to
increase the probability of a secure
transaction

FTP – Download and Upload files
What Can I Do on the Internet,
continued …
Create Blogs – Internet personal journal /
Micro-Blogs - shorter version, like Twitter
 WIKIS – Like a blog but can be edited by
any user
 Social networking
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 Twitter
 Facebook
 You
Tube
 Skype
Internet Terminology
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Protocol
TCP/IP
Domain Name
Hypertext
Link
HTTP
E-Mail
IP Address
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URL
Web Page
Cookie
HTML
bps
Webmaster
Plug-Ins
WI-FI HotSpots
Tabbed Browsing
Definitions
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Protocol- The rules & guidelines computers must
follow to exchange information on the Internet or on
a network. Several Internet protocols must be present
TCP/IP (Transport Control/ Internet Protocol)- the
language spoken between computers on the Internet.
All data has to be in TCPIP format
Top Level Domain (TLD)- The address mechanism
used on the internet to identify a server. Kind of like
a file extension. ex., .edu, .com, .mil, .gov, .biz
Definitions, continued …
Hypertext- A cross-reference web software
feature that helps the user transfer to a web
page at another site. Links are created to
allow the user to move (or link) easily from
one document to another
 Link- An underlined reference within a web
page that when clicked upon, transfers a
user to another web page or site.
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E-Mail- A system that lets computer users exchange
messages with other computer users electronically.

The messages go to an email server instead of directly to
the end recipient. The recipient must then retrieve the mail
from the server.
Email, continued …
 Email also allows me to create attachments – send files along
with an email message
 Microsoft Hotmail provides an “Online storage drive” (Microsoft
SkyDrive – check appendix C)
Definitions, continued …
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IP Address - Most Internet hosts or servers use
“static” IP addresses. Most other computers use a
temporarily assigned IP address referred to as a
“dynamic” IP address. The IP address identifies a
device while on the Internet. Without one, you can’t
get on the Internet. Dynamic IP addresses are
provided by your ISP
Web page - contains information on a particular topic
or location and often provides links to other pages

URL (Uniform Resource Locator)- Address of an
individual web page – no blank spaces in a URL
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HTTP (Hypertext Transport Protocol)- A protocol used
to transfer hypertext documents between computers on
the WEB.
Cookie - File installed on a user’s hard drive by a web
site to remember a user’s preferences and settings
HTML - Hypertext markup language is a code used to
develop web pages. Today web authoring software such
as “FrontPage” and “homepage” makes web page
development fairly simple
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Definitions, continued …
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bps - The speed at which information is
transferred between computers is measured in bits.
Common bit units are kilobits and megabits
Webmaster - Person who maintains or develops
web sites
Plug-Ins – free “helper applications” or “add-ons”
that assist a browser in performing some type of
task – Shockwave and Flash are examples
WI-FI HotSpot – an area in which the public can access
a wireless connection to the Internet, usually for free
Definitions, continued …
 Tabbed Browsing – easier to keep track of your
browsing sites during your session. Supported by
most current or new browsers
 Portal – a web site that offers a variety of
Internet services from a single location (MSN,
Yahoo, PasPort)
This is a sample of a Web Page
Internet Interfaces
- Browsers 
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MOSAIC – 1st graphical browser - created my Marc
Andreessen
Microsoft Internet Explorer - (IE) most popular (first appeared
for free in Windows 95)
Lynx (non-graphical)
Opera – developed in Norway in 1996, an alternative to IE and
Firefox
Mozilla Firefox – Ranks #2 behind only Internet Explorer /
“Camino” is the “Mac” version
Safari – popular on the “Mac”
Google Chrome
Others – check the Internet
What Internet tools allow me to search for
information?
SEARCH ENGINES! - Search engines are like the
yellow pages in the phone book where you can look
up a topic or category and obtain the addresses to
web sites – some search engines also include
“Subject Directories” which enhance the experience
(see your book) / Boolean operators such as “AND”
& “OR” enhance & refine the search
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AltaVista
Yahoo – also features “AlltheWeb.com”
Lycos
Web Crawler
Excite
Google
Dogpile
Ask
Internet II
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A separate “high speed” Internet for “select” universities,
industry, and the U.S. military
Commercial free
Primarily for research
Web 2.0
New wave of web-based services
emphasizing online collaboration and
sharing – it’s happening now / Web
3.0 (Semantic web) is on the way
The World Wide Web Consortium
(W3C)
Over 350 Organizations from around the world oversee
research and set standards and guidelines for many areas
of the Internet
Security & Ethical Issues on the Internet
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Pornography - not how to find it but how to
censor it from minors
Hazards / Malware - guarding against viruses,
spy ware and unauthorized access
Crime - stalking, theft, hate propaganda,
sabotage
Logos, Patents and Copyrights - other users
may steal your ideas – little protection
Communications infrastructure – Bandwidth.
Telephone lines were not intended for Internet
traffic, current equipment is too slow
CDA - Censorship through the “computer
decency act”. Can lawmakers go too far and
control what we can and cannot do on the
Internet? Recently “SOPA” (Stop Online
Piracy Act) caused concern
THE END
-Happy Surfing-