What is a computer network?
After buying a new computer, the first thing you probably do is try to connect it to the Internet. To do this, you will establish a connection to the router, which receives data from the Internet and transmits it to the computer.
But that’s not all, you may also want to connect a printer, your smartphone or your TV to the router so that these devices are also connected to the Internet. You will have networked several devices via a central switching point and thus created your own network. But what does this mean exactly?
What is a computer network?
In information technology, a network is defined by the linking of at least two computer systems by means of a cable or wireless radio link. The most basic network consists of two computers connected by a cable. It is also referred to as a peer-to-peer (P2P) network. This type of network has no hierarchy: the two participants are at the same level. Each computer has access to the other’s data and they can share resources, such as a storage disk, programs or peripherals (printer, etc.).
Modern networks are generally a little more complex and involve much more than just two computers. For systems with more than ten participants, a client/server configuration is usually used. In this model, one computer acting as the central switching point (server) makes its resources available to the other network participants (clients).
Example of a network: home WLAN
A good example of a small client/server network is the home WLAN (wireless local area network). The various devices in the house are connected by radio to the router, which acts as a central node (server) within the house. In turn, the router is then connected to a much larger network: the Internet.
Since the devices (clients) are connected to the router, they can use the same resources as the server, namely the Internet, since they are part of the network. What’s more, the devices can also communicate with each other without the need to establish a direct connection each time.
Before networks were established in their current form, communication between computers and peripherals was complicated to say the least. Computers were connected using a LAN cable. Mechanical network switches were required to use the peripherals together.
If you want a particularly stable connection, despite the practical advantages of WLAN, it is best to use a wired connection to the router and the individual devices.
What are the functions and advantages of a network?
The main function of a network is to provide the participants with a platform for exchanging data and the common use of resources. This function is of such crucial importance that it would be very difficult to imagine our everyday life and the world of work today without the existence of networks.
In addition, in many offices there is only one or a few printers, which are used by everyone. Without a network, each computer would have to be connected to the printer, which would be very tedious. A network cleverly solves this problem, since all computers are connected to the printer via a central node.
The main advantages of networks are therefore :
- Data sharing
- Resource sharing
- Centralized management of programs and data
- Centralized data storage and backup
- Sharing computing power and storage capacity
- Simple administration of permissions and responsibilities
How does a network work?
In a classic client/server network, there is a central switching point, the server. The server is connected to the other devices, which are called clients. The connection can be wired (LAN) or wireless (WLAN).
In a classic home network, the router acts as the server. It is connected to the Internet and makes the “Internet” resource available to other devices (computer, smartphone, etc.).
In networks of a certain size, e.g. in a company, the server is usually a mainframe computer. This computer does not run ordinary applications and programs, but special server software and services. The server has to run continuously, unlike other computers (clients), which can be turned off.
In this kind of server-based network, the communication between the server and the client is as follows: the client first sends a request to the server. The server examines the request and then sends back the desired data (Response). In this model, it is always the client that contacts the server, never the other way around.
Network protocols ensure the smooth communication between the different network components. They regulate the exchange of data, determine how communication is initiated and terminated and which data is transferred. There are usually several network protocols, each of which assumes a certain sub-function and is arranged hierarchically in layers.
In addition to this, it is important to ensure that the transmitter and receiver are correctly assigned. For this purpose, so-called network addresses are used. Within the network, each computer usually has an IP address that uniquely identifies it, just like a telephone number. This internal IP address is only used for communication between members of the local network.
What types of networks exist?
Most often, networks are categorized into different types of networks according to the mode of data transmission and their range.
Mode of transmission
As far as the mode of transmission is concerned, a distinction is made between wired and wireless networks. Examples of wireless networks are WLANs, which are based on the IEEE 802.11 standard (international name: Wi-Fi), and LTE technology, which is used by cell phones and smartphones. Wired networks, such as DSL, are also referred to as “high-speed Internet”.
The following categories are used for network reach:
- Personal Area Network (PAN)
- Local Area Network (LAN)
- Metropolitan Area Network (MAN)
- Wide Area Network (WAN)
- GAN (Global Area Network)
Note that these different types of networks overlap in part. The user of a WLAN is at the same time part of a WAN or GAN as soon as he is connected to the Internet.