When you buy a new computer, the first thing you do is connect it to the internet. To do this, you must establish a connection with the router , it receives the data from the internet and then transfers it to the computer..
But this is not all; In another step, you can also connect a printer, a smartphone or a television to the router , so that all these devices are also connected to the internet. Thus, you will have used a central switching element to interconnect different devices and create your own network.
What exactly does this mean?
In computing, a computer network involves the connection of at least two computer systems , either by cable or, wirelessly, by radio frequency. The simplest network is the connection of two computers using a cable. In these cases, there is talk of a network peer to peer . Here there are no hierarchical differences, both participants are at the same level. Both computers have access to the data on the other computer and can use shared resources such as storage memory, programs, or peripherals (printers, etc.)..
Today's computer networks tend to be a bit more complex and have more elements than just two computers. In systems with more than two participants, client-server networks are used by default . In this case, a computer acts as a central switching element (server) and makes its resources available to the other network participants (clients).
A computer network involves the connection of two or more computers or other electronic devices that allows the exchange of data and the use of common resources..
We have already mentioned the WLAN (Wireless Local Area Network or Wi-Fi network), a perfect example of a small server-client network . The different devices in the home are connected to the router by radio frequency and it functions as a central node (server). The router, in turn, is connected to a much larger network: the Internet.
As the devices are connected to the router as clients, they can use the same resource as the server, that is, the Internet, since they are part of the network. Furthermore, the devices can communicate with each other without the need for a direct connection. You can, for example, send a print order from your computer to a WLAN-capable printer without connecting that printer to your computer using a cable.
Before today's computer networks were established, communication between different computers and terminals was very complicated. The connection between computers was made with LAN cables. The mechanical switch boxes ( switches ) allowed the shared use of peripherals. But, due to the physical limitation (the length of the cable), the devices and computers had to always be close.
If you need a particularly stable connection , you should consider direct cable connection to the router or the corresponding device despite the great convenience that Wi-Fi offers.
The main task of a computer network is to provide a platform for data exchange and sharing of resources to participants. This task is so important that it is hard to imagine much of our day-to-day and work environment without computer networks.
Let's look at a practical example: in a conventional office, each workstation has its own computer. Without a connection between computers, it would be very difficult for a team to carry out a common project, since there would be no common point to share or store digital documents or information and collaborators would not be able to use certain programs together as we are used to today. in day.
Also, in many offices there is only one printer, or only a few for shared use. Without a network, technicians would have to connect each computer to the printer, a technically inconvenient solution. The computer network solves this problem in the most elegant way, since all the computers are connected to the printer through a central node .
Main advantages of computer networks:
In a conventional client-server network, there is a central switching point, the so-called server . The server is connected to the other devices, which are called clients . The connection can be wireless ( WLAN ) or wired ( LAN ).
In a conventional home computer network, the router acts as a server. It is connected to the Internet and makes Internet access available to other devices (computer, mobile phone, etc.).
When it comes to larger networks, for example, in a company, the server is usually a central computer . This computer does not run conventional applications or programs, but server-specific software and services. The server must always be up and running, while the other computers (clients) can be shut down without problem.
In a server-client network, communication between both elements is carried out as follows: first, the client makes a query ( request ) to the server; the server evaluates the query and transmits data ( response ) . In this model, it is always the client that contacts the server, never the other way around.
So that communication between the different components of a computer network can be carried out without complications, there are so-called network protocols. These protocols regulate the exchange of data and determine how communication is established and terminated and what data is transmitted. As a general rule, there are several network protocols, they are organized in different hierarchical layers and each one takes care of a partial task.
You also have to ensure that the sender and receiver can be assigned correctly. For this, there are network addresses. In computer networks, each computer usually has an IP address to identify it unequivocally, something similar to telephone numbers. This internal IP address is only used for communication between the participants on the local network. In Internet communication, on the other hand, external IP addresses are used that the Internet provider assigns automatically.
Also, a distinction is made between IPv4 addresses and IPv6 addresses . IPv4 addresses were the standard at the time, but only approx. 4.3 billion of these addresses. Due to the enormous growth of the Internet, more IP addresses were soon needed. For this reason, the new IPv6 standard has been developed, which allows generating up to 3.4 x 10 38 (in words: 340 sextillion) different addresses. A number that should be sufficient for the future.
You can consult more detailed information about the IP protocol and its determining role in computer networks in our article What is the Internet protocol? .
Networks are divided into different types of networks according to the type of transmission and its scope , based on how, where and in what range the data is transmitted.
Regarding the type of transmission, a distinction is made between radio frequency networks and cable networks . An example of a radio frequency network is WLAN networks, based on the IEEE 802.11 standard (international name: Wi-fi) or LTE technology in mobile phones and smartphones . Cable networks like DSL networks are also called broadband Internet.
The scope of the networks is classified as follows:
You must bear in mind that the network types partially overlap. As a user of a WLAN network, you are using a WAN or GAN network as soon as you connect to the Internet.