The term computer network stands for a collection of computer systems and their various hardware. All the computers in a network have an interconnection among them which is established through communication channels. The resources as well as the information are transmitted and received through these channels only. In every computer system in the network, there is at least one device that can receive or send the data to and from some other device or process in another computer system of the same network. Then these two systems are said to form a network.
In simple terms we can say that a collection of devices is called a network. Networks can be classified based up on a number of criteria such as the following:
1. Medium used for the transportation of the data
2. Communication protocols
3. Scale used
4. Topology formed
5. Benefit of the network
6. Scope of the organization and so on.
The data formats and rules that are used for the exchange of the data are defined by the communication protocols in a network. Also, the basis for the programming of the network is also provided by the communication protocols only.
Below mentioned are some of the important parts of a communication protocol:
1. Two Ethernet
2. A link layer standard and hardware for LANs
3. The internet protocol suite (for defining protocols for internet).
Internet working involves three main things namely:
1. Establishing the data communication between a numbers of networks.
2. For host to host data transfer.
3. Formats for data transmissions specific to an application.
There are number of fields of which the computer network is considered to be a sub – discipline such as:
1. Electrical engineering
3. Computer science
4. Information technology
This is so because it mostly relies up on the practical applications and theoretical disciplines of these fields. Before the advent of the actual computer networks, the communication between two machines or systems was performed through manual transmission of information i.e., the human user has to carry the instructions between the two. A number of characteristics features that we observe in today’s internet were present in the earlier internet too.
Properties of Computer Network
Following are the properties of a typical computer network:
1. Facilitation of the communication: It helps people in communicating with ease and efficiency via several sources such as:
a) E – mail
b) Instant messaging (IM)
c) Chat rooms
e) Video telephone calls
f) Video conferencing
2. Sharing of data, information and other types of files: In a network, the accessing of the information stored on different computers by authorized users is common. However the efficiency with which all this is done depends up on the capability of the network to provide the access to the data, info and files on devices that are shar-able.
3. Sharing of networks and resources: Often in a network one computer accesses and uses resources provided by the other computers and devices that might be present in the network. This is achieved through distributed computing using resources spread across the network.
4. A computer network may or may not be insecure since computer hackers may use it for indecent purposes such as for deploying a virus or worm or for stealing data or for inducing denial of service attacks.
5. A computer network may or may not interfere with the other technologies such as ADSL or VDSL (last mile access technologies).
6. Some computer networks are easy to set up while others are not because of their complexity. Setting up an effective network can prove to be very costly especially for large organizations.
Types of Communication Media
There are a number of communication media as mentioned below:
1. Wired media: It includes twisted pair wires, coaxial cable and optical fibers.
2. Wireless technologies includes terrestrial microwave, satellites, infrared systems, GAN etc.
3. Exotic technologies such as IP over avian carriers, internet over interplanetary dimensions and so on.