A network, in computing, is a group of two or
more devices that can communicate. In
practice, a network is comprised of a number
of different computer systems connected by
physical and/or wireless connections.
A network of networks in which user of any
computer can get information from other
computers, if they have permission.
◦ An internet (note the lowercase letter) is two or more
networks that can communicate with each other.
◦ It is a generic term used to mean an interconnection of
◦ The second is the name of a specific world wide
◦ The most notable internet is called INTERNET (uppercase
letter), in which connect more than hundreds of
thousands interconnected networks.
◦ a communications system that connects computers and
databases all over the world
An intranet is an organization’s network,
that uses internet protocols, network
connectivity to securely share part of an
organization information or operation with its
an intranet belonging to an organization ,
usually a company, accessible only by the
organization’s members, employees, or
others with authorization.
An extranet is designed to connect the offices of
a large organization situated in metropolitan
Extranet is simply an external network.
Intranet is accessible only to people who are
members of the same company or organization,
An extranet provides various levels of
accessibility to outsiders like company with its
customers, suppliers, or other business partners.
You can access an extranet only if you have a
valid username and password.
Extranets are becoming a very popular means for
business partners to exchange information.
An Internet service provider (ISP) is a company that
provides customers with Internet access. Data may
be transmitted using several technologies, including
DSL, cable modem, wireless.
International ISPs: the international ISPs that connect
nations together example, Comcast, cox, centurylink
National ISPs: The national ISPs are backbone
networks created and maintained by specialized
Regional ISPs: The regional ISPs are smaller ISPs that
are connected to one or more national ISPs.
Local ISPs: The local ISPs provide direct services to
the end users.
ISP(internet service provider) list of Pakistan.
ISP city Website
Asia net Lahore www.asia.net.pk
Brain net Karachi,lahore www.brain.net.pk
Click online Peshawar www.click.net.pk
Comsats Islamabad, www.comsats.net.pk
Iqra Net Peshawar www.iqranet.net
Every computer on the internet has a unique internet
address (similar to telephone number),
An Internet Protocol address (IP address) is a numerical
label assigned to each device connected to a computer
network that uses the Internet Protocol for communication
Static IP addresses
◦ When a computer uses the same IP address every time it connects
to the network, it is known as a static IP address.
Dynamic IP addresses
◦ In situations when the computer’s IP address changes frequently.
It is called a dynamic IP address.
◦ Don't tattoo your IP address to your arm, because it's not really
yours. Even at home it can change if you do something as simple
as turn your modem or router on and off. Or you can contact your
Internet service provider and they can change it for you.
The world wide web (commonly abbreviated as “the
web”) is a system of interlinked hypertext documents
accessed via the internet.
The World Wide Web (WWW), also called the Web, is
an information space where documents and
other web resources are identified by Uniform
Resource Locators (URLs), interlinked
by hypertext links, and accessible via the Internet
Introduced in 1990 by Tim Berners-lee
Allows computer users to locate and view
It allows users to explore and retrieve text and
graphics from web sites.
◦ A web site is a collection of web pages with some common
◦ Like books web sites contain information and consist of
◦ A web site may consist of many pages or just a single page.
◦ A world wide web page
◦ The individual pages that make up a web site.
◦ You can view a single web page at a time.
When accessing a web site, the first page displayed is usually
the home page. Often, like a book’s table of contents, it gives
information about what is available on that site.
This is simply the first page displayed when you connect to the
internet, or , the starting point of your internet session.
Application software that allows users to view web content
such as text, images, videos, music games and other
information located on a web page at a web site on the
A program on a computer that accepts requests for
information, processes the requests and allows you to
navigate to resources on the internet.
Microsoft internet explorer
Web browsers were introduced by companies like Mozilla,
Netscape, and Microsoft. More recently, Google entered
the browser market with Google chrome
On the web, you navigate- commonly known as browsing
◦ One way to navigate the www is by clicking on a
◦ A link is an area of a web page that , when you click
on it, will take you from the page you are presently
viewing to another page either within the same site
or to an entirely different site.
◦ Links can be anything on a page.
◦ Graphical or textual elements
◦ Underlined text: images, color varies but is often
blue, objects in motion etc.
Uniform resource locator is a fancy term for the address
of a world wide web page or other resource.
Used to identify web pages
protocol Hostname File path
The first part is protocol “:http://”
Second is host name (domain name) or is the fully
qualified domain name.
The term “domain name” usually refers only to the last
part of the host name, in this case “vbs.com” which has
been registered for that particular company’s exclusive
The third part of the URL “welcome/main.html” is the
path at which this particular web page is located on the
DNS server translate symbolic name( such as
www.sharq.edu.af) into numerical IP address.
Symbolic names are a great convenience because
they are easier to remember than numerical
For example, the domain name (www.example.com)
might translate to 126.96.36.199.
It is like a phone book.
DNS helps users to find their way around the internet.
http://www.google.com here the domain name is
The www is not necessary.
The .edu is the top level domain-the top level
in which a site wants to register.
The second level domain is typically the
company, organization or brand name for
.com: it is used for commerical websites.
.edu: it is used for educational websites eg
.gov: Government institutions.
.org: for organization.
.mil: used for military websites eg
.net Networking organizations, it represents
an organization that is working on network.
.ca: used for canada.
.th: used for Thailand.
A communication protocol is set of rules that
control data communication.
The protocol determine the following:
How the sending device will indicate that it has
finished sending a message.
How the receiving device will indicate that it has
received a message.
A protocol defines what is communicated, how it is
communicated, and when it is communicated.
https:// HyperText Transfer Protocol
◦ HTTPs is the protocol that supports communication
between web browsers and web servers.
◦ Hypertext Transfer Protocol Secure (HTTPS) is an extension
of the Hypertext Transfer Protocol (HTTP) for secure
communication over a computer network, and is widely
used on the Internet.
◦ Protocol for client/server communication
◦ Very simple request/response protocol.
Client sends request message
Server replies with response message
SMTP: Simple Mail Transfer Protocol
FTP: File Transfer Protocol
POP: Post Office Protocol
SMTP is used to relay the mail messages to the
mail relay server. Hence it is used to transfer
FTP : "File Transfer Protocol." FTP is
a protocol designed for transferring files
over the Internet.
POP is used to Download/Receive messages
from a mail server and store it locally on
A server is a computer, a device that is
dedicated to managing network resources.
Servers are often referred to as dedicated
because they carry out hardly any other tasks
apart from their server tasks.
There are a number of categories of servers,
including print servers, file servers, and
In theory, whenever computers share
resources with client machines they are
Modulator-demodulator. Electronic device that allows
computers to communicate over telephone wires,
One computer's modem converts its digital signals
(which cannot be sent efficiently over phone lines)
into analog signals (which can be). The other
computer's modem reconverts the analog signals
(that the computer cannot understand) into digital
signals (that it can). Conversion of one type of signals
to another is called modulation, their reconversion to
the original type is called demodulation. Modern
modems work at 56 thousand bits per second or
higher data transfer speeds, perform automatic error
correction, and allow voice and fax communications.
Notas do Editor
A dial-up connection to the Internet: is a connection that uses a modem and a conventional telephone line
"Digital Subscriber Line." DSL is a communications medium used to transfer digital signals over standard telephone lines.
STAN TELECOM LTD (STAN TELECOM)
Afghanistan Faiz Satellite Communication (AFSAT)
Afghan ICT Solution.
Unique Atlantic Telecommunication LTD.
An Internet Protocol address (IP address) is a logical numeric address that is assigned to every single computer, or any other device that is part of a IP-based network.
The Internet Protocol (IP) is the method or protocol by which data is sent from one computer to another on the Internet. Each computer (known as a host) on the Internet has at least one IP address that uniquely identifies it from all other computers on the Internet.
The "IP" part of IP address stands for "Internet Protocol." The "address" part refers to a unique number that gets linked to all online activity you do...somewhat like a return address on a letter you'd send out. (All this happens in milliseconds.)
Multimedia is content that uses a combination of different content forms such as text, audio, images, animations, video and interactive content.
Hypertext is text displayed on a computer display or other electronic devices with references (hyperlinks) to other text that the reader can immediately access,
A Uniform Resource Locator (URL), colloquially termed a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it.
us /ˈnæv·ɪˌɡeɪt/ to direct the way that a vehicle, esp. a ship or aircraft will travel, or to find a direction across, along, or over an area of water or land: [ T ] He learned to navigate these waters. [ I ] Whales navigate by visual means.
the activity of moving from site to site on the Internet: Surfing
the action or process of moving or being moved. motion
Hypertext Transfer Protocol Secure (HTTPS) is an extension of the Hypertext Transfer Protocol (HTTP). It is used for secure communication over a computer network, and is widely used on the Internet.
Clients (web browsers) send requests to web servers for web elements such as web pages and images.\
HyperText Transfer Protocol Secure (HTTPS) is an encrypted version of HTTP, which is the main protocol used for transferring data over the World Wide Web. HTTPS protects the communication between your browser and server from being intercepted and tampered with by attackers
Domain Name Servers (DNS) are the Internet's equivalent of a phone book. They maintain a directory of domain names and translate them to Internet Protocol (IP) addresses.This is necessary because, although domain names are easy for people to remember, computers or machines, access websites based on IP addresses. DNS servers eliminate the need for humans to memorize IP addresses such as 192.168.1.1 (in IPv4).
IP address is your phone number, and DNS is a phone book, where people may find this phone number.
DNS (or also known as Domain Name System) is a system that matches domain names like Google.com or Yahoo.com to the right IP addresses.
This system is a database of domain names and IP addresses. It has been using to maintain a directory of domain names and helps to translate these domain names to the right IP addresses.
Stands for "File Transfer Protocol." FTP is a protocol designed for transferring files over the Internet.
FTP: is also the Internet standard for moving or transferring files from one computer to another using TCP or IP networks/internet.
Stands for "Internet Message Access Protocol" and is pronounced "eye-map." It is a method of accessing e-mail messages on a server without having to download them to your local hard drive. This is the main difference between IMAP and another popular e-mail protocol called "POP3." POP3 requires users to download messages to their hard drive before reading them. The advantage of using an IMAP mail server is that users can check their mail from multiple computers and always see the same messages. This is because the messages stay on the server until the user chooses to download them to his or her local drive. Most webmail systems are IMAP based, which allows people to access to both their sent and received messages no matter what computer they use to check their mail.
early all personal computers are capable of serving as network servers. However, usually software/hardware system dedicated computers have features and configurations just for this task. For example, dedicated servers may have high-performance RAM, a faster processor and several high-capacity hard drives. In addition, dedicated servers may be connected to redundant power supplies, several networks and other servers. Such connection features and configurations are necessary as many client machines and client programs may depend on them to function efficiently, correctly and reliably.
In the client/server model, a file server is a computer responsible for the central storage and management of data files so that other computers on the same network can access the files. ... A program or mechanism that enables the required processes for file sharing can also be called a file server.
A database server is a computer system that provides other computers with services related to accessing and retrieving data from a database.
What Is a Print Server? A print server, or printer server, is a device which connects printers to computers over a network. All print jobs are sent from the computer to the server, which then sends the print job out to a printer.
A fax modem enables a computer to transmit and receive documents as faxes on a telephone line. A fax modem is like a data modem but is designed to transmit and receive documents to and from a fax machine or another fax modem. Some, but not all, fax modems do double duty as data modems. As with other modems, fax modems can be internal or external. Internal fax modems are often called fax boards.
In the early 1990s small business PCs commonly had a PC-based fax/modem card and fax software (typically WinFax Pro). Largely replaced by email, PC-based faxing with a fax/modem declined at the turn of the century. Where faxing from a PC is required there are a number of Internet-based faxing alternatives. Where businesses still had one or more traditional fax machines churning out pages, they were usually outnumbered by PCs processing E-mail.
A router is a networking device that distributes (or routes) your internet connection from your modem to all of your devices, such as mobile phones, laptops, desktop computers, and smart TVs. This enables them all to connect to the internet at the same time. A router also makes it possible for different devices to communicate with one another over the network.
There are many different types of routers, but two of the popular ones are wired and wireless routers. Wired (or hard-lined) routers need to be physically connected to a modem and a device with cables. In comparison, wireless routers use built-in antennas to communicate with other devices on your WiFi network. However, a wireless router still needs to be physically connected to your modem with a cable to send and receive information from the web.