Computer Network and its Classification

                               COMPUTER NETWORK:

A network is defined as a system for connecting computers using a single transmission technology. The computers can communicate with each other in a network. They can send and receive data from each other when they are in a network.

INTERNET:

The Internet is defined as the set of networks connected by routers that are configured to pass traffic among any computers attached to any network in the set. By internet many computers which are at longer distances from each other can communicate with each other.

CLASSIFICATION OF NETWORKS:

Computer networks are classified on four factors which are as follow:

1. Size
2. Connectivity
3. Medium
4. Mobility

1. Size:

Network are classified in two types according to size.

1. Local Area Network. ( LAN)
2. Wide Area Network (WAN)

In LAN network occupies the smaller area like a room a floor or a building.

In WAN, network occupies larger areas like cities & countries. Internet is a Wide Area Network.
LAN & WAN are compared by the speed of transmission, bandwidth and latency, management, security, reliability, billing and their standards.

2. Connectivity:

Networks are also classified into two topologies according to connectivity.

1. Point-to-Point
2. Broadcast

Point-to-Point:

In Point-to-Point topology there are two topologies.
a. STAR topology

In star topology each computer is connected to a central hub. The communication takes place through the hub.
b.TREE topology
In Tree topology all computers are connected to each other in such a way that they make a tree.

Broadcast:

In broadcast topology there are further two categories
a. Satellite\Radio
b. Ring topology
In a satellite or radio topology all computers are connected to each other via satellite or radio wave.

3. Medium:

Classification of networks is also based on the Medium of transmission. Mediums of transmission are as follow.

1. Copper wire
2. Co-axial cable
3. Optical fiber
4. Radio waves

All these mediums differ from each other with respect different parameters. These parameters are speed of transmission, range of the receiver and transmitter computer, sharing of information, topology, installation & maintenance costs and reliability. For example the range of radio waves will be much more than an optical fiber. Similarly other mediums differ from each other and appropriate medium is selected for the sake of transmission.

4. Mobility:

Networks are also classified according to their mobility. In this regard there are two types of networks.

1. Fixed networks
2. Mobile networks

In these days mobile networks are the hot case. Mobile networks have been emerged in the last decade. In this respect there are some issues which are attached with the mobility of networks which are as follows:

• Location and tracking
• Semi persistent connections
• Complex administration and billing as devices and users move around the network.

Written By: Asad Hussain