Introducing NetworksBy

www.aiict.com

Admin By: Mansoor Ali Shar

Instructor

Network Administration & System Administration

Agenda

Networks

Why Networks (Need)

Types

Logical Classification

What is a Computer or Data

Network?

What is Network and Networking?

A network is the physical connectivity of the nodes (Computers, Switches, Routers, Modems, Printers, Servers etc) through some sort of media for the purpose of sharing resources and accessing valuable information is known as Network. A great example of a network is the Internet, connecting millions of people all over the world together.

Where as Networking is the Physical and logical connectivity of these nodes. Physically how they are connected with each other and logically how data is transferred between these nodes.

What is Computer Network? A computer network

is a group of computer systems and other computing hardware devices that are linked together through communication channels to facilitate communication and resource-sharing among a wide range of users. Data is transferred in the form of Protocol Data Unit (PDU).

Why Computer

Networks?

?

Computer Networks

Before the advent of Computer Networks business activities were carried out manually i-e paper work

Much amount of information caused information searching and analysis more difficult

Information exchange took hours even days to get there causing late in critical decisions

Lets go 55 years backYes!

1960s60s

History

Mid 1960s

Mainframe Computers in research organizations were standalone devices (No more networks)

Need

Advance Research Projects Agency (ARPA) in Department of Defense (DoD) had funded some researcher, and the researchers needed to share their findings with each other. ARPA decided to have such an infrastructure that could provide facility to exchange information thereby reducing costs.

History Cont… 1967

ARPA had meeting with Association for Computing Machinery (ACM) and presented the idea for ARPANET

ARPANET A small network →of connected computers

ARPANET Idea Each host computer

would be attached to a specialized computer called Interface Message Processor (IMP)

Each IMP had to be able to communicate with each other IMPs as well as with its own attached host

History Cont… 1969 (ARPANET First

Implementation)

Four nodes The University of California at Los Angeles (UCLA), The University of California at Santa Barbara (UCSB), Stanford Research Institute (SRI) and University of Utah were connected via IMPs to form a network

A Software called Network Control Protocol (NCP) provided communication between the hosts

04 & 02 Node ARPAnet Diagram

Todays Network Requirement

Business decisions have to be made ever more quickly

Decision makers require immediate access to data/ information

Data is supposed to be confidential hence require security

Network Types There are several different types of computer networks. Computer networks

can be characterized by their size as well as their purpose.

The size of a network can be expressed by the geographic area they occupy and the number of computers that are part of the network. Networks can cover anything from a handful of devices within a single room to millions of devices spread across the entire globe.

Some of the different networks based on size are:

a) LAN

b) WAN

c) MAN

d) PAN

Local Area Network

A local-area network (LAN) is a computer network that spans a relatively small area such as a home, school, computer laboratory, office building or group of buildings.

Wide Area Network

A wide area network, or WAN, occupies a very large area, such as an entire country or the entire world. A WAN can contain multiple smaller networks, such as LANs or MANs. The Internet is the best-known example of a public WAN.

Metropolitan Area Network

A metropolitan area network, or MAN, consists of a computer network across an entire city, college campus or small region. A MAN is larger than a LAN, which is typically limited to a single building or site. Depending on the configuration, this type of network can cover an area from several miles to tens of miles. A MAN is often used to connect several LANs together to form a bigger network. When this type of network is specifically designed for a college campus, it is sometimes referred to as a campus area network, or CAN.

Personal Area Network

A personal area network - PAN - is a computer network organized around an individual person. Personal area networks typically involve a mobile computer, a cell phone and/or a handheld computing device such as a PDA. You can use these networks to transfer files including email and calendar appointments, digital photos and music.

Adhoc Network

Adhoc network (also called IBSS “independent basic service set”) is a temporary network between computers without Intermediary devices or Access Point (AP) i.e switches or Routers. The range for this network is typically 30 feet.

Internet

The Internet is a worldwide, publicly accessible network of interconnected computer networks that transmit data using the standard Internet Protocol (IP).

The Internet is a collection of interconnected computer networks, linked by copper wires, fiber-optic cables, wireless connections, etc.

Web is a collection of interconnected documents and other resources, linked by hyperlinks and URLs.

The World Wide Web is one of the services accessible via the Internet, along with various others including e-mail, file sharing, online gaming etc.

Intranet

Intranet. An Intranet is a private network that is contained within an enterprise. It may consist of many interlinked local area networks and also use leased lines in the wide area network. The main purpose of an Intranet is to share company information and computing resources among employees.

Extranet

An extranet can be viewed as part of a company's Intranet that is extended to users outside the company like suppliers, vendors, partners, customers, or other businesses.