INTERNET AND COMMUNICATIONS TECHNOLOGY

Part 2

DATA TRANSMISSION Transmission methods used Bandwidth: The speed at which Data can be

carried.

BANDWIDTH Narrow Band Technology provides bandwidth that is

less than 64 Kb or less. Can be found in telephones lines as well.

BANDWIDTH Voiceband Technology capable of transmitting

spoken comunication.

BANDWIDTH Broadband Technology provides bandwidth that is

greater than 64Kb per secs or more.

COMMUNICATION MODES Broadcasts Point – to – point

BROADCASTS Radio and television stations use this

method to send information to as many of their users as possible.

POINT-TO-POINT This is a direct communication channel

between two computers on a network. Example: When one person calls

another a wireless path is created between those two persons. So this ensures that other people in the same vicinity can not receive the call other than who the call is really meant for.

DATA TRANSMISSION Data travels over a medium in three

ways: Simplex Half-Duplex Duplex

SIMPLEX Simplex Transmission is uni-directional

HALF-DUPLEX Data transmission is bi-directional, but

only in one direction at a time.

DUPLEX Data transmission is bi-directional and

permits transmission in both directions at the same time.

DATA COMMUNICATIONS Internet Intranet Extranet

INTERNET Internet is a public, global network

based on TCP/IP protocol. TCP/IP protocol assigns every

connected computer a unique address, also called an IP address.

So any two computers can locate each other.

INTRANET This is a private computer network

designed to meet the needs of a single organization or company .

It is not necessarily open to the external internet and definitely not opened to users.

It uses similar facilities such as a browser and web pages.

EXTRANET This is an intranet that has been

selectively opened to strategic allies, or associates or even customers.

An online banking application is a good example of this.

INTERNET CONCEPTS Data communications all over this

world is based on the TCP/IP protocol. Communications with the world wide

web is based on a different protocol HTTP Others include: FTP, VoIP, Wi-Fi and

Bluetooth.

HTTP Hyper Text Transfer Protocol This is a protocol used to request and

transmit files, especially web pages and web page components over the internet or computer networks

FTP File Transfer Protocol This is a protocol used to transfer files

between FTP servers and clients.

VOIP Voice over IP This is the use of Internet-based

technologies to transmit voice-grade data over the internet.

Great example can be seen with the use of SKYPE, Voice notes in Whats App

BLUETOOTH This is a wireless protocol for

exchanging data over short distances from fixed and mobile devices, using radio waves.

Bluetooth capabilities are enabled in a device via a Bluetooth chip.

WI-FI This is a marketing term and is found in

several protocol governing the wireless LAN communications.

THE WORLD WIDE WEB There is a large collection of documents

or data called web pages. Web pages are grouped together to

form Web Sites, and stored on Web Servers, downloaded and displayed on users’ computer by a web browser.

WEB PAGE A web page is a document written in

Hyper Text Markup Language (HTML), that may contain text, sound, images, video clips, hyperlinks and other components.

WEB SITE A web site is a group of web pages that

belong together and are linked to each other using hyperlinks.

Organizations want viewers to be able to find documents on their web site easily.

HYPERLINKS A hyperlink is an icon, information

object , underlined or otherwise emphasized word or phrase that displays another document when clicked with the mouse.

WEB SERVER A web server is a special-purpose

application software that accepts requests for information, framed according to the Hyper Text Transport Protocol (HTTP).

It processes these requests and sends the requested document.

A WEB BROWSER A web Browser is a special-purpose

application software that runs on an Internet connected computer and uses the HTTP to connect with web servers.

URL Uniformed Resource Locator. This is a string of charactters that

uniquely identifies an internet resourec’s type and location. Concider the following:

URL http://www.tabs.ultimate-guitar.com/c/

christina_perri/a_thousand_years_ver2_crd.htm http:// Identifies a World Wide Web Document www.tabs.ultimateguitar.com – Indicates the

Internet domain name of the computer on which the document is stored.

/c/christina_perri/a_thousand_years_ver2_crd.htm – fully describes the directory structure and includes the document’s name.

COMMUNICATING GLOBALLY Several factors contribute to

communication globally. E-MAIL IRC BULLETIN BOARDS BLOGGIN PODCASTS

E-MAIL Electronic mail, applications allow users

to send an electronic document over a network to anyone with an e-mail address.

An e-mail address is always in the form username@domain_name, for example slbintech@hotmail.com.

Text based, send images power points, videos

IRC Internet Relay Chat Is a messaging system that allows

users to ‘chat’ with text other people over the internet using text messages.

Windows Live Messenger, Face Book Chat, Google Chat, Yahoo Chat, e.t.c.

BULLETIN BOARDS AND NEWSGROUPS This is an electronic forum that hosts

posted messages and articles related to common subjects.

A newsgroup is an on-line discussion group or forum specifically focused on a particular area of interest.

BLOGGING A blog or a web log is a diary

maintained by its author on the World Wide Web. It allows people to comment on the posts.

PODCASTS A podcast is an audio broadcasts using

the Internet that can be played back on an Ipod or similar device.

RESEARCH / HOME WORK Which of the cable types mentioned do

you believe: (a) has the greatest Bandwidth (b) is the most costly to purchase and

install (c) is the most common in Local area

network

RESEARCH / HOME WORK Suggest one reason why a residential

householder would want to purchase a 8MB broadband Internet Service.

Suggest THREE ways in which an extranet may typically be used by an organisation

What is Top-Level-Domain Give three examples of Top-Level-

Domain.