why we are doing it and using it so dedicatedly
To wrap up all history to know why we need it
INTRODUCTION
Each of the past three centuries has been dominated by a single technology.
The eighteenth century was the time of the great mechanical systems accompanying the Industrial
Revolution.
• The nineteenth century was the age of the steam engine.
• During the twentieth century, the key technology has been information gathering,processing and distribution.
These areas are rapidly converging, and the differences between collecting, transporting,storing and processing information are quickly disappearing.
The old model of a single computer serving all of the organisations computational needs, is rapidly being replaced by one in which a large number of separate, but interconnected computers do the job. These systems are called computer networks.
Therefore computer network means an interconnected collection of autonomous computer,
“If one computer can forcibly start, stop or control another one, the computers are not
autonomous”.
NEED OF COMPUTER NETWORKS
Computer Network satisfy a broad range of purposes and meet various requirements.
Need of computer network arises for various purposes, and these are:
1. To provide sharing of resources such as information or processors.
2. To provide inter-process communication among users and processors.
3. To provide distribution of processing functions.
4. To provide centralised control for a geographically distributed system.
5. To provide centralised management and allocation of network resources.
6. To provide compatibility of dissimilar equipment and software.
7. To provide network users with maximum performance at minimum cost.
8. To provide an efficient means of transport large volumes of data among remote
locations.
NETWORK MODELS
1. Centralised network model: Here the terminals allows user has to enter data. But
the processing is done on the server. It gives the ability to the user to access the
data from the remote location.
2. Distributed network model: Here data storage and processing is done on the local
computer. Hence the computers used in the distributed network are capable of
working as stand alone. But can be network together to increase functionality.
In a large network it is not easy to find a path and routes it gets confusing and unmanageable to overcome this issue Routing and Switching come into existance by using its features one can easily manage smaller or bigger network.
now comming on point
What Are Routing and Switching?
The way a network operates is to connect computers and peripherals using two pieces of equipment – switches and routers. These two let the devices connected to your network talk with each other as well as talk to other networks.
Though they look quite similar, routers and switches perform very different functions in a network:
fig:-switches
- Switches are used to connect multiple devices on the same network within a building or campus. For example, a switch can connect your computers, printers and servers, creating a network of shared resources. The switch would serve as a controller, allowing the various devices to share information and talk to each other.
Through information sharing and resource allocation, switches save you money and increase productivity.
There are two basic types of switches: managed and unmanaged.- An unmanaged switch works out of the box and does not allow you to make changes. Home-networking equipment often will have unmanaged switches.
- A managed switch allows you access to program it. This provides greater flexibility because the switch can be monitored and adjusted locally or remotely to give you control on how traffic travels over the network and who has access to your network.
fig:-routers
- Routers are used to tie multiple networks together. For example, you would use a router to connect your networked computers to the Internet and thereby share an Internet connection among many users. The router will act as a dispatcher, choosing the best route for your information to travel so that you receive it quickly.
Routers analyze the data being sent over a network, change how it is packaged and send it to another network or over a different type of network. They connect your business to the outside world, protect your information from security threats, and can even decide which computers get priority over others.
Depending on your business and your networking plans, you can choose from routers that include different capabilities. These can include functions such as:- Firewall: specialized software that examines incoming data and protects your business network against attacks
- Virtual Private Network (VPN): A way to allow remote employees to safely access your network remotely
- IP Phone network : Combine your company’s computer and telephone network, using voice and conferencing technology, to simplify and unify your communications.
Networking 