internet and cyberspace.pdf

7/27/2019 Internet and Cyberspace.pdf

1/25

Company

LOGO

Instructor: Ch. Bilal Ahmad Khan

Internet and Cyberspace


2/25

History of Communication and

Internet

Slide Rule-1621

Mechanical Adding Machine -1642

Ada Lovelace - 1843

Telegraph Message Machine - 1844

First Telephone - 1876


3/25

History of Communication and

Internet

First Radio Signal - 1895First Radio Broadcast -1907

First ATM - 1963


4/25

Internet Operation


5/25

Internet Operation


6/25

Applications of Internet


7/25

Data Transmission Capacity

Bandwidth, or channel capacity, is an expressionof howmuch data - text, voice, video, and so on

- can be sent through a communications channel

in a given amount of time

The type of data transmission that allows only onesignal at a time is called baseband transmission

several signals can be transmitted at once, its called

broadband transmission

Broadband - very high speed - connections

Fiber Optics, DSL, cable, and satellite and other

wireless connections


8/25

Physical Connection for Internet

Wired Dialup

ISDN

DSL T1

Wireless

Through Air Link (e.g. PTCL EVO, Wateen,Wi-Tribe)

Satellite


9/25

Data Transmission Speed

bps Bits per second

Eight bits equals one character, such as A, 3, or # Kbps

Kbps

kilobits per second 1 thousand bits per second

Mbps

megabits per second

1 million bits per second

Gbps

gigabits per second

1 billion bits per second


10/25

Connecting with Internet

Narrowband Dialup Connections

Connecting with Modem

Modems and Call Waiting

Source: Using Information Technology by William and Sawyer


11/25

Connecting with Internet

High Speed Phone Lines ISDN (Integrated Services Digital Network)

consists of hardware and software that allow

voice, video, and data to be communicated

over traditional copper-wire telephone lines

DSL (digital subscriber line) uses regular

phone lines, a DSL modem, and special

technology to transmit data in megabitspersecond

T1 line, essentially a traditional trunk line that

carries 24 normal telephone circuits and has a

transmission rate of 1.5 to 6 Mbps


12/25

Connecting the Internet

Source: Using Information Technology by William and Sawyer


13/25

Wireless Connections

Satellite Communications Communications satellite, a space station that transmits radio

waves called microwaves from earth-based stations

Wi-fi

802.11 standards by IEEE of wireless transmissions

Transmission of data at up to 54 Mbps

300-500 feet covered by access point

2G

Used for mobile communications

3G High-speed wireless technology that does not need access

points because it uses the existing cell phone system


14/25

Working of Internet

Client computer requesting data or services

Normally a computer in front of user

Server Is a central computer supplying data or

services requested of it

Also known as host computer


15/25

Working of Internet

Point of Presence Local access point to the internet

A collection of modems and other equipment in a local

area

POP acts as a local gateway to the ISPs network Network Access Point

A routing computer at a point on the internet where

several connections come together

Owned by a network service provider Internet Backbone

High-speed, high-capacity transmission lines that use

the newest communications technology to transmit data

across the internet


16/25

Working of Internet


17/25

Working of Internet

Protocols Set of rules, that computers must follow to transmit data

electronically

The protocol that enables all computers to use data

transmitted on the internet is called Transmission

Control Protocol/Internet Protocol, or TCP/IP,

Packets

TCP/IP breaks the data in a message into separate

packets

Fixed-length blocks of data for transmission

IP Address

Internet Protocol (IP) address uniquely identifies every

computer and device connected to the internet


18/25

World Wide Web

Design and DevelopWeb Site

Choose the name of

website

Buy domain name

with Web Host

Web Host provides

web space Upload files to the

web server

Write the URL in theweb browser

Browse the website

Client Server

DatabaseSend

RequestRequest

Data

Fetch

DataFetch

Reply


19/25

World Wide Web

Design and DevelopDatabase

Design and Develop

Web Site

Choose the name of

website

Buy domain name

with Web Host Web Host provides

web space

Upload files to theweb server

Write the URL in theweb browser

Browse the website

Client Server

Database

Data

SQL Query

Send

RequestRequest

Data

Fetch

DataFetch

Reply


20/25

World Wide Web

URL URL (Uniform Resource Locator) is a string of

characters that points to a specific piece of

information anywhere on the web


21/25

World Wide Web

Protocol (http://) HyperText Transfer Protocol (HTTP) , the communications rules

that allowbrowsers to connect with web servers

Another protocol is ftp://

Domain Name

Domain is simply a location on the internet, the particular web

server

Directory Name

The directory name is the name on the serverfor the directory,

or folder, from which your browser needs to pull the file File Name

The file is the particular page or document that you are seeking


22/25

Search Engines

Search services are organizations that maintain databases

accessible through websites to help you find information on the

internet

Search engines are programs that enable you to ask questions or

use keywords to help locate information on the web

Spiders - also known as crawlers, bots (for robots), or agents thatcrawl through the World Wide Web, following links from one

web page to another and indexing the words on that site


23/25

Search Engines

Individual Search Engines Compiles its own searchable database on the web

Hits are defined as the sites that a search engine

returns after running a keyword search

Examples are Bing, Yahoo, Google etc

Subject Directories

Created and maintained by human editors, not

electronic spiders, and allows you to search for

information by selecting lists of categories or topics

Examples are Galaxy, Google Directory, LookSmart,

Open Directory Project, and Yahoo! Directory


24/25

Search Engines

MetaSearch Engines Allows you to search several search

engines simultaneously

Examples are Clusty, Dogpile, Mamma,MetaCrawler, and Webcrawler etc

Specialized Search Engine

Help locate specialized subject matter, such

as material about movies, health, and jobs

Examples are imdb, expedia, rozee, career

etc

Emails and More Modes of


25/25

Emails and More Modes of

Communication

Simple Mail Transfer Protocol

Post Office Protocol Version 3

Internet Message Access Protocol

internet and cyberspace.pdf

Documents