Internet

greydullΔίκτυα και Επικοινωνίες

30 Οκτ 2013 (πριν από 3 χρόνια και 11 μήνες)

91 εμφανίσεις



INTERNET


The Internet, popularly knows as the

Net
, is a worldwide system of

computer networks, it is also called a

network of networks
.



It connects millions of computers

worldwide together, forming a network

in which computers can communicate

with each other.


TCP/IP


Transmission Control Protocol/


Internet Protocol) is the basic

communication language or protocols


of the Internet.



TCP/IP is a two
-
layer program.




TCP layer, manages the assembling of a

message or file into smaller packets that are

transmitted over the Internet and received

by a TCP layer that re
-
assembles the


packets into the original message.

IP



The Internet Protocol layer used for data

transmission, it handles the address of each

packet and allow packets to be routed


through networks.





Each gateway computer on the network

checks this address to see where to forward

the message.




IP Address






The IP Address is the numeric address that

guides all Internet traffic, such as e
-
mail


and Web traffic, to its destination.




Typical IP address is 165.113.245.2

Backbone



It is a wide area transmission path

that

carries data gathered from smaller lines.




Backbone is a line or channel of lines


that connect you to a wide area network.




Channel responds to several multiple


interconnected commercial, government,

academic and other high
-
capacity data


routes across globe.


HTTP



Hypertext Transfer Protocol defines how

messages, requests and information are

formatted and transmitted between servers

and browsers




It is the set of rules for exchanging files

(text, graphic images, sound, video, and

other multimedia files) on the World Wide

Web.




when user enter a URL in your browser, this

actually sends an HTTP command to the

Web server directing it to fetch and transmit

the requested webpage.

HTML




Hypertext Markup Language the basic

language

that is used to build hypertext

documents and code manages that how


webpages are formatted and displayed on

the WWW.




It use, plain text documents, but when

those documents are interpreted by the Web

browser the document can display

formatted text, color, a variety of fonts,

graphic images, special effects, hypertext

jumps to other Internet locations.

WWW


World Wide Web or simply
Web
, is a
method of

accessing information

over the Internet.



The Web uses the HTTP protocol, that transmit

data between client and server and allow

applications to communicate all sort of data and

information.



The Web also utilizes browsers to access

Web

documents called WebPages (contain graphics,

sounds, text and video) that are linked to each

other via hyperlinks.





URL or Uniform Resource Locator is the techie term

for the location of a file or resource on the Internet.



ISDN


Integrated Services Digital Network (ISDN)

is sort of telephone network which use

switching circuit for Voice and data

communication simultaneously.



A switching system that establishes a


connection between host and destination

for a certain duration called session.



Integrated services means voice, data,

image and video services over the digital

telephone network using a single telephone

line.

Leased Line




Leased line is a permanent telephone

connection between two points set up


by a central switch office on a fixed

monthly/yearly rate




This line remain always active



(24
-

hour/7
-
days
-
a
-
week) to connect two

or more geographically distant locations.




Typically used by enterprises, Research,



TV stations, Aircraft and corporate.

PSTN


Public Switched Telephone Network,


it is normal telephone communication

system being used in our telephone

exchanges.



This is narrowband type network and

designed for

voice traffic.

Bandwidth



Bandwidth is the width for range of frequencies



on a given transmission medium.



It is a data transmission rate means


maximum amount of information



(bits/second) that can be transmitted



along a channel




In computer networks, bandwidth is often used as

amount of data that can be carried from one point

to another in per second of time.




Bandwidth is speed or capacity of a network

connection, more bandwidth means faster data

transmission.

DSL


Digital Subscriber Line referred as xDSL


is a digital line being provided by local

telephone exchange or network.



It is

high speed Internet connection

(Broadband) and supports more data speed

to downstream

and slower speed to



upstream.



DSL lines operates on one pair of wires as

a normal analog phone or land line

work.

Gateway



Gateway is a networking hardware

act

as entrance to another network or

interface two or more different



networks.










It is a mechanism, providing




access to another kind system or


network which has different kind of


network, protocols or

environment.






ROUTER


Router is central switching device in a


packet
-
switched network (Internet) that

directs and controls the flow of data packets

over networks.



A typical router is connected to at least two

networks, LANs or WANs or a LAN
-
ISP


network.



Routers use headers and routing tables to

determine the best path for forwarding the

packets.


Fire Wall



Firewall based on hardware and software

system which separates LAN into two or

more parts for security purposes.




It is filtering systems which control and

restrict the flow of data between network

and computer systems. It is sort of antivirus

system or protecting shield.



It blocks IP addresses, protocols or any

type of application for security purposes.



Browser


Web Browser is a software used to make

contact with Web sites on both the


Internet and Intranet.





Internet Explorer




Mozila Firefox




Google Chrome




Apple Safari




Opera (Mac)




Netscape Navigator






Web Site


Website is a location on the WWW or Internet that

contains specific topic information or collection of

related web pages of text, doc, images, videos

or

other digital assets it is also called

e
-
brochure.



Domain Name is a unique name that identifies an

Internet site. Domain Names always have 2 or

more parts, separated by dots, following are types

of various domains



Education
-





edu

Government
-




gov

Military






mil

International
-




int

Network






net

Non
-
profit Organization
-


org

Commercial





com


Search Engine



A search engine is a bulk database of many

Web pages or information on the WWW.



A search engine generally returns the

result typed request.





Google




Yahoo




MSN




Alta Vista




Lycos




Excite




Hot Bot




Infoseek




Web Crawler

Brief History of Internet


Advanced Research Projects Agency (ARPA)

was the network that became the basis for

the Internet



ARPA was the project U.S Deptt of Defence

(DoD) that uses this communication facility

in 1969.


Internet was first known as the ARPANET.



The original aim was to create a network

that would allow computers of one

university to be linked with Research

Institutes and other universities for sharing

information and experience without any

physical movement.

E
-
mail


Electronic Mail is a system of world
-
wide

electronic communication in which a

computer user can compose a message at

one terminal that can be received at the

recipient's terminal.



It is a mechanism of transmitting text

messages alongwith necessary attachments

in any format using Simple Mail Transfer

Protocol (SMTP) and Post of Protocol (PoP)

as a core communication method.





E
-
mail Services



Online Services









Yahoo




Hotmail




Gmail




MSN




AOL




Rediff mail



Off
-
line Services










Outlook Express




Eudora




Pegasus