NETWORKING FUNDAMENTALS

INTRODUCTIONA computer network is a collection of interconnected computers and otherdevices which are able to communicate with each other and share hardwareand software resources.

The term interconnected meansthat there exists a path through which data can be transmitted from one computer / device to another.

BENEFITS OF A NETWORK

• Information Sharing

• Hardware Sharing

•Software Sharing

•Time efficient

• Cost saving

TYPES OF NETWORKS

LAN

WAN

MAN PAN

PAN (personal area network)

Network of Communicating devices (Computer, Phone, MP3/MP4 Player, Camera etc.) in the proximity of an individual.

Covers an area of a few meters radius.

Can be set up using guided media (USB cable) or unguided media (Bluetooth, Infrared).

LAN (local area network)

Network of computing/Communicating devices inA room, A building, or A campus.

Covers an area of a few meters to a few kilometres radius.

Usually contains a single LAN, or sometimes one building can contain a few small LANs (Like some schools have independent LANs in each computer lab.).

Can be set up using guided media or unguided media.

If a LAN is setup using unguided media, it is known as WLAN (wireless LAN).

MAN (Metropolitan Area Network)

Network of computing/communicating devices within a city.

Covers an area of a few kilometres to a few hundred kilometres radius.

A network of schools, or banks, or Government offices etc., within a city, are examples of MANs.

All types of communication media (guided and unguided) are used to set up a MAN.

Typically owned and operated by a single entity such as a government body or a large corporation.

WAN (wide area network)

Network of computing/communicating devices crossing the limits of a city, country, or continent.

Covers an area of over hundreds of kilometre radius.

A network of ATMs, BANKs, National Government Offices, International Organizations' Offices etc., spread over a country, continent, or covering many continents are examples of WANs.

All types of communication media (guided and unguided) are used to set up a WAN.

The best known example of a WAN is the internet.

COMMUNICATION MEDIUM

GUIDED(Wired)

UNGUIDED

(Wireless)

TwistedPair

Cable

Co-axialCable

Optical FiberCable

RadioWaves

MicroWaves

Infrared

Waves

OPTICAL FIBER CABLE

RADIO WAVES

MICROWAVES

INFRARED WAVES

SATELLITE

NETWORK TOPOLOGIES

A Topology is an arrangement of physical connections among nodes in a network.A Node is a device, which is directly connected to a computer network. It can be a computer or any other device like printer, scanner etc.

Bus TopologyIn bus topology all the nodes are connected to a main cable called backbone. If any node has to send some information to any other node, it sends the signal to the backbone.A small device called terminator is attached at each end of the backbone. When the signal reaches the end of backbone, it is absorbed by the terminator and the backbone gets free to carry another signal.

Star TopologyIn star topology each node is directly connected to a hub/switch. If any node has to send some information to any other node, it sends the signal to the hub/switch. In the case of a switch the signal is sent only to the intended node(s). Star topology generally requires more cable than bus topology.

Tree TopologyTree topology is a combination of bus and star topologies. It is used to combine multiple star topology networks. All the stars are connected together like a bus. This bus-star hybrid approach supports future expandability of the network

Ring TopologyA ring network is a network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node - a ring. Data travels from node to node, with each node along the way handling every packet..

NETWORK PROTOCOLSA network protocol is a set of rules for communication among networked devices.Protocols generally includes rules of how and when a device can send or receive the data, how is the sent data packaged, and how it reaches its destination.There are a number of protocols defined for computer networks. Some of them are : • File transfer protocol (FTP) – used to transmit files.• Simple mail transfer protocol (SMTP) – used to

transmit e-mail messages.• Post office protocol (POP) – allows the recipient to

retrieve messages.• Wireless application protocol – enables wireless

devices to access and use the Internet using a client/server network.

NETWORK DEVICESOther than the transmission media many other devices are required to form computernetworks. Some of these devices are:

• NIC : Network Interface Card is a device that enables a computer to connect to a network and communicate.

• Hub : A Hub is an electronic device that connects several nodes to form a network andredirects the received information to all the connected nodes in broadcast mode.

• Switch : A Switch is an intelligent device that connects several nodes to form a network and redirects the received information only to the intended node(s).

• Repeater : A Repeater is a device that is used to regenerate a signal which is on its waythrough a communication channel. A repeater regenerates the received signaland re-transmits it to its destination.• Gateway : A Gateway is a device, which is used to connect different types of networks and perform the necessary translation so that the connected networks cancommunicate properly.