How a network works
Since telephone lines are used as communication links between devices, each computer must be connected via a modem (modulator / demodulator) to access the network. The modem modulates the digital signal of a computer so that it can travel through the phone line. It also demodulates incoming signals from the phone line back into digital signals which can be read by the computer.
Computers on a network must follow a protocol for the exchange of data. On the Internet, this is called “Transmission Control Protocol / Internet Protocol” (TCP/IP).
Separate LANs can be connected by bridges (if they use the same protocol) or by gateways (if they use different protocols), in order to form larger networks. Intra-nets are private networks that include Internet features and are commonly used by large organizations to provide their users with certain facilities such as e-mail. Intra-nets are particularly useful because they grant organizations a better access, control and protection of their data.
Local Area Network
A LAN (Local Area Network) is a small network that interconnects a limited area such as a house or an office, whereas a WAN (Wide Area Network) links devices from a large area or even from all around the world.
A LAN usually consists of servers, hosting files and services that other LAN users can access. The users can also share files and resources among each other. In a LAN, all the connected devices are called ‘nodes’, and they can be linked together in different ways, from linear to bus and star shaped.
A network is composed of different devices, each one with a different job:
- The router directs the traffic of data around the network
- The server stores data and allows other devices to access it
- A client is any device which requests and receives data from a server. The vast majority of devices on a network are clients
Instead of using a server, clients can also exchange data directly between one another. This is called “peer-to-peer” (P2P) communication.