COMPUTER NETWORKINGCOMPUTER NETWORKING

INTRODUCTION-What is networking? A network is a collection of computers and devices connected to each other. The network allows computers to communicate with each other and share resources and information. In other words networking can be defined as inter-connection of two or more computers for sharing the resources(hardware and software)and provide security on them. Networks are built with a combination of computer hardware and computer software.

LAN (LOCAL AREA NETWORK)

WAN (WIDE AREA NETWORK)

MAN (METROPOLITAN AREA NETWORK)

PAN (PERSONAL AREA NETWORK)

VPN (VIRTUAL PRIVATE NETWORK)

CAN (CAMPUS AREA NETWORK)

GAN (GLOBAL AREA NETWORK)

SAN (STORAGE AREA NETWORK)

Local area networks (LANs) are computer networks ranging in size from a few computers in a single office to hundreds or even thousands of devices spread across several buildings.

LANs in turn may be plugged into larger networks, such as larger LANs or wide area networks (WANs), connecting many computers within an organization to each other and/or to the Internet.

Typically, connected devices share the resources of a single processor or server within a small geographic area (for example, within an office building).

Usually, the server has applications and data storage that are shared in common by multiple computer users.

A wide area network (WAN) is a computer network that covers a broad area (i.e. any network whose communications links cross metropolitan, regional, or national boundaries).

WAN is a network that uses routers and public communications links.

The largest and most well-known example of a WAN is the Internet. A WAN is a data communications network that covers a relatively broad geographic area (i.e. one city to another and one country to another country) and that often uses transmission facilities provided by common carriers, such as telephone companies.

WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.

A metropolitan area network (MAN) is a network that connects two or more local area networks or campus area networks together but does not extend beyond the boundaries of the immediate town/city.

Routers, switches and hubs are connected to create a metropolitan area network.

The term is applied to the interconnection of networks in a city into a single larger network (which may then also offer efficient connection to a wide area network).

It is also used to mean the interconnection of several local area networks by bridging them with backbone lines.

A personal area network (PAN) is a computer network used for communication among computer devices close to one person.

Examples of devices that are used in a PAN are :printers, fax machines, telephones, PDAs and scanners.

The reach of a PAN is typically about 20-30 feet approximately 6-9 meters.

A network consists of two or more computers that are linked in order to share resources (such as printers and CD-ROMs), exchange files, or allow electronic communications.

The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.

A linear bus topology consists of a main run of cable with a terminator a each end. All nodes (file server, workstations, and peripherals) are connected to the linear cable. Ethernet and Local Talk networks use a linear bus topology.

Linear bus structure

A star topology is designed with each node (file server, workstations, and peripherals) connected directly to a central network hub or concentrator.

Data on a star network passes through the hub or concentrator before continuing to its destination. The hub or concentrator manages and controls all functions of the network.

star structure

The ring topology is a type of computer network configuration where each network computer and device are connect to each other forming a large circle.

Each packet is sent around the ring until it reaches its final destination.

Ring structure

It requires that every terminal should be attached to each other.

All the computers must have adequate number of interfaces for the connections to be made. Because of this requirement the installations is somewhat difficult.

The length of cable required is quite higher as compared to other topologies.

Mesh structure

A tree topology combines characteristics of linear bus and star topologies.

It consists of groups of star-configured workstations connected to a linear bus backbone cable.

Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs .

Tree structure

All networks are made up of basic hardware building blocks to interconnect network nodes, such as Network Interface Cards (NICs), Bridges, Hubs, Switches, and Routers.

In addition, some method of connecting these building blocks is required, usually in the form of galvanic cable .

Less common are microwave links or optical cable (“optical fibre"). An Ethernet card may also be required.

Some of the basic components required for interconnecting the network nodes:

NETWORK INTERFACE CARD REPEATERS NETWORK HUB NETWORK BRIDGE NETWORK SWITCH ROUTER

The main reasons are:

Distribute pieces of computation among computers (nodes) .

Coordination between processes running on different nodes .

Remote I/O Devices .

Remote Data/File Access .

Personal communications (like e-mail, chat, audio/video conferencing).

World Wide Web .

  It's a 32 bits, 4-part period delimited, decimal number called IP number or IP

address:

www.xxx.yyy.zzz

Each part can vary from 1 to 254 (0 and 255 are reserved for the net and the broadcast).

Each network interface card attached to the Internet mast have an unique IP address.

The IP address can be splitted in two parts: Network. Host.

Data from,Parag Jayant

Design by Nikhil Mishra,Sujested by Ravi Panday, Prasant Tyagi,