– A computer network or an information network can be defined as a collection of computer systems and hardware which are interconnected via many communication channels through which resource and information sharing becomes possible.
– In information network, in every device there is at least one process that sends and receives data to and from at least one process in another device at a remote location, then the two devices are said to form a network.
– In simple words ,we can say that a group of devices connected to each other is called a network.
Networks can be classified on the basis of characteristics such as following:
1. Medium used for the transportation of the data
2. Communications protocol used
5. Organization scope
– The rules and data formats for exchange of information are defined by the communications protocol in a computer network.
– These protocols only provide a foundation for network programming.
– Some of the communication protocols include hardware, 2 Ethernet and a link layer network ubiquitous in the internet protocol suite and the local area networks.
– A set of protocols for inter-networking is defined by the internet protocol suite.
– These protocols facilitate the communication among the multiple networks, data transfer from host–to–host, application–specific data transmission formats.
– Computer networking in some cases can be considered:
1. Electrical engineering
3. Computer science
4. Computer engineering
5. Information technology
Characteristics of Information Network
Below we discuss the characteristics of the information network:
1. Facilitate communications:
It lets people communicate through network with efficiency and ease via services such as chat rooms, instant messaging, video conferencing, video telephone calls, and telephone and so on.
2. Allow sharing of data, files, and other type of info:
In a network, users are allowed to access information and data that is stored on other systems in the network. This capability of networks to provide access to info and data stored on shared storage devices is unique feature of the information networks.
3. Share network and computing resources:
Resources available on a network can be accessed by each computer system on that network. For example, same printer might be used by all the systems on the network for printing purposes. Another example is of distributed computing.
4. May be insecure:
Networks might be insecure since computer hackers might use it for deploying worms and viruses on the devices that are connected to the network, in order to introduce denial of service attacks.
5. Interference with other technologies:
Some forms of radio communication are strongly disturbed by the power line communication. An example of this is amateur radio. Interference might also occur with VDSL and ADSL (last mile access technologies).
6. Difficult to set up:
Information networks are quite difficult to set up depending up on their complexity.
Very costly to set up an information network that is effective.
Classification of Computer Networks
– Computer networks might be classified based up on associated software technology and hardware used for interconnecting the individual devices present on a network like:
1. Electrical cable
2. Optical fiber
3. Radio waves
– All these are located at the level 1 and 2 of the OSI layer.
– Ethernet as defined by IEEE 802 is a well – known family of the communication media.
– Devices without wiring require wireless LAN technology for enabling connection between them.
– These devices make use of the infrared signals or radio waves as a medium for transmitting the signals.
– Common communication protocols are:
2. Internet protocol suite
3. SONET/ SDH
4. Asynchronous transfer mode
– Programs that communicate over network are written by a process called computer network programming.