Networks

Computers and Internet have tremendously changed this world and our living style to a great extent. It is sure that without this technology, today’s day to day life is not easier. 

Networking connects multiple devices together to share the information. These networks can be formed using different means like cables, telephone lines, satellites, and radio waves.

 What is Network?

A network is nothing but a group of devices that can be communicated with each other through a link. The internet is one of the best examples of network. The internet is a network of networks.

Normally, networks are classified into diferent properties anmely topology, protocols and architecture. The topology specifies the arrangement of the network. A protocol specifies the common set of rules to be used. An architecture is a set of rules and methods that describes the functions, organisations and implementation of computer systems.

Networking Elements
A computer network contains the following main elements:
1. Minimum two computers
2. Transmission medium (wired or wireless)
3. Protocols
4. Network Software

Goals of Computer Networks
The following are some of the important goals of computer networks:
1. Resource Sharing: The resources can be shared from one computer to many computers. For example, in most of the organization, the common devices like printers, scanner, fax, modem is shared among the users. This saves money too.

 2. Flexible access: The files can be accessed from any computer in the network.

3. High Reliability: All files can be replicated on one or two systems. If one system is not working or not available, the other systems can be used. It provides an alternate solution.

Network Criteria
There are certain criteria in networking namely.
1. Performance
2. Reliability
3. Security

Performance:
It is normally measured in terms of transmitting time and the response time. Transmitting time is the time taken to send the data from a source to the destination. The response time is the total time taken to respond to a request for any service. 

Some of the common metrics used to measure the performance include bandwidth, packet loss, throughput, latency.

Reliability:
Reliability is measures in terms of frequency of failures and recovery from failures. The higher the number of failures, the lesser will be the reliability.

Security:
It defines how the data are protected from unauthorized users.