A computer network is a collection of PCs and other devices connected together with cables, so that they can communicate with each other for the purpose of sharing information and resources. Networks vary in size: some are within a single office, others span the globe.
There are various network technologies, the most common being Ethernet and Fast Ethernet. A network can be made up of one or more of these technologies. Ethernet and Fast Ethernet networks operate in a similar way, the main difference is the speed at which they transfer information; Ethernet operating at 10 Megabits per second (Mbps) and Fast Ethernet operating at 100 Megabits per second (Mbps).
How does a network work?
Devices on a network communicate by transmitting information to each other in groups of small electrical pulses (known as packets). Each packet contains address information about the transmitting device (the source address) and the intended recipient (the destination address). This address information is used by some of the network equipment to help the packet reach its destination.
Ethernet and Fast Ethernet networks use a protocol called CSMA/CD (Carrier-sense Multiple Access with Collision Detection). This protocol operates by allowing only one device to communicate at any given time. When two devices try to communicate simultaneously, a collision occurs between the transmitted packets, and this is detected by the transmitting devices. The devices stop transmitting and wait before resending their packets. All this is part of normal network operation for Ethernet and Fast Ethernet networks, and is comparable to a conversation between people in a group; if two people speak at the same time, they both stop and then one will start to speak again.
What are the benefits of networking?
Creating a network, by connecting computer equipment together, allows the equipment to communicate and share information and resources. In particular, you can:
- Share expensive peripherals, such as printers — All of the computers can access the same printer.
- Pass data between users without the use of flash drives or CD ROM disks — Files can be copied and accessed across the network, eliminating the time wasted and inconvenience caused by using floppy disks to transfer files. There is also less restriction on the size of file that can be transferred over the network.
- Centralize key computer programs, such as finance and accounting programs — It is often important that all users have access to the same program (and not copies of it) so that they can work on it simultaneously (for example, a ticket booking application where one program must be used to ensure that the same tickets are not sold twice). Networking allows offices to have such a central program that all users can access.
- Automate backup of critical files — It is always essential to keep backups of any important files. You can automate this procedure by having a computer program that backs up the files for you. Without a network, you would have to manually copy files, which is time consuming.
What are the components of a network?
A small network generally consists of:
- PCs and peripherals (such as printers)
- Network cables
- A piece of network equipment such as a hub or a switch, that connects your PCs and peripherals
- A network operating system (NOS) — Windows®, Macintosh or Linux can be used as a NOS
- Other pieces of network equipment may be required. For example, some PCs are not ready for use in a network; they may require network interface cards (NICs) to provide the connections they need.