Modern world scenario is ever changing. Data Communication and network have changed the way business and other daily affair works. Now, they highly rely on computer networks and internetwork.
A set of devices often mentioned as nodes connected by media link is called a Network.
A node can be a device which is capable of sending or receiving data generated by other nodes on the network like a computer, printer etc. These links connecting the devices are called Communication channels.
Computer network is a telecommunication channel using which we can share data with other coomputers or devices, connected to the same network. It is also called Data Network. The best example of computer network is Internet.
Computer network does not mean a system with one Control Unit connected to multiple other systems as its slave. That is Distributed system, not Computer Network.
A network must be able to meet certain criterias, these are mentioned below:
1. Performance
2. Reliability
3. Scalability
It can be measured in the following ways:
· Transit time : It is the time taken to travel a message from one device to another.
· Response time : It is defined as the time elapsed between enquiry and response.
Other ways to measure performance are :
1. Efficiency of software
2. Number of users
3. Capability of connected hardware
It decides the frequency at which network failure take place. More the failures are, less is the network's reliability.
Computer Networks: Security
It refers to the protection of data from any unauthorised user or access. While travelling through network, data passes many layers of network, and data can be traced if attempted. Hence security is also a very important characteristic for Networks.
1. Interpersonal Communication: We can communicate with each other efficiently and easily. Example: emails, chat rooms, video conferencing etc, all of these are possible because of computer networks.
2. Resources can be shared: We can share physical resources by making them available on a network such as printers, scanners etc.
3. Sharing files, data: Authorised users are allowed to share the files on the network