What is a computer network? Types, Examples, Basic Elements…etc..

We explain what a computer network is, the elements that compose it and how it is classified. In addition, advantages and disadvantages.

What is a computer network?

A computer network, a data communications network or a computer network is the interconnection of different number of computer systems  through a series of telecommunications devices and a physical medium (wired or wireless).

Its function is to share information in data packets . They are transmitted by electrical impulses, electromagnetic waves or other means, using special coding. For this, the system translates the processes of the different computers into the same language, through a series of communication standards .

Computer networks are not different, in their exchange logic, from other communication processes: they have a sender, a receiver and a message, a means through which to transmit the message and a series of codes or protocols to ensure their correct understanding . Only, in this case, those who send and receive messages are computers.

By having a number of networked computers, we can create an internal communication between them, which also serves to share Internet access points or peripheral management (such as a printer). In addition, it allows the fast sending of data and files without the need to use secondary storage devices (such as disks or pen-drives).

Networks are present today in almost every day, especially those related to bureaucracy or resource management. In fact, the Internet connection that we access from our computer , cell phone or other devices is nothing more than an immense network of computers.

Types of computer networks

Commonly, computer networks are classified, first, according to their scope and geographic size:

• LAN networks . Its name comes from the Local Area Network (in English: “Local Area Network”), as they are smaller and larger networks, such as those that may exist between computers in the same booth or cyber café.
• VLAN : it is a type of logical or virtual LAN, mounted on a physical network, in order to increase security and performance. In special cases, thanks to the 802.11Q protocol (also called QinQ), it is possible to mount virtual networks on WAN networks. It is important not to confuse this implementation with VPN technology.
• MAN networks . Its name comes from the Metropolitan Area Network (in English: “ Metropolitan Area Network ”) and designates intermediate-sized networks, such as those used in large libraries or large companies , connecting different areas and geographically remote from each other.
• WAN networks . Named for the acronym of Wide Area Network (in English: “ Wide Area Network “), these are large and wide-ranging networks, such as the global network of networks, the Internet.
• WLAN (Wireless Local Area Network) or wireless local area network : it is a LAN network that uses wireless means of communication. It is a widely used configuration due to its scalability and because it does not require installation of cables.
• PAN (Personal Area Network) or personal area network : it is made up of devices used by a single person. It has a range of a few meters. WPAN (Wireless Personal Area Network) or wireless personal area network: it is a PAN network that uses wireless technologies as a medium.
• CAN (Campus Area Network) or campus area network : it is a network of high-speed devices that connects local area networks through a limited geographical area, such as a university campus, a military base, etc. It does not use public media.

There are other possible classifications of computer networks, according to their specific topology, their functional relationship or data directionality.

Basic elements of a computer network

Commonly a computer network contains the following elements:

• Server . Computers in a network do not have the same hierarchy, nor do they perform the same functions. For example, servers are responsible for processing the data flow of the network, serving all other connected computers (ie, “serving them”) and centralizing the control of the network itself.
• Clients or work stations . These are the computers that do not serve others, but are part of the network and provide access to it, requesting resources managed by the server.
• Transmission media . It refers to wiring, electromagnetic waves, or the physical environment that allows the transmission of network information, whatever.
• Hardware elements . All the technological pieces that enable the physical establishment of a network, that is, that allow it. We talk about network cards, modems and routers, or repeater antennas that extend the connection wirelessly.Devices connected to a computer network can be classified into two types: those that manage access and communications in a network (network devices), such as modem, router, switch, access point, bridge, etc .; and those that connect to use it (end-user devices), such as computer, notebook, tablet, cell phone, printer, smart TV, video game console, etc.Those who use a network, in turn, can fulfill two roles (classification of networks by functional relationship): server, where the device provides a service for anyone who wants to consume it; or client, where the device consumes one or more services from one or more servers. This type of network architecture is called a client / server.On the other hand, when all the devices on a network can be clients and servers at the same time and it is impossible to distinguish the roles, we are in the presence of a point-to-point or peer to peer architecture . Different types of architectures coexist on the Internet.
• Software elements . Similarly, it requires programs to manage and operate communications hardware for each workstation, including the Operating System Networking (US, of the English Network Operating System ), which also sustain the operation of the network, provides antivirus and firewall services ; as well as thecommunicative protocols (TCP / IP) that allow the machines to share the language.
• Connection speeds: The speed at which information travels in a network is given by the maximum speed supported by the means of transport. Among the most common means we can affirm that optical fiber is the fastest, with approximately 2 Gbps; then twisted pair follows, with 100 Mbps to 1000 Mbps; and finally, Wi-Fi connections, with 54 Mbps on average. Speeds may vary according to network protocols used.

Advantages of a computer network

A computer network is a very useful and valuable tool to centralize and disperse the stored information of a type of organization (companies, institutions, etc.). It is so important in the contemporary world that we use them constantly without even realizing it.

Thanks to computer networks we can perform all kinds of operations quickly and over huge distances. Some of them are:

• Social interactions , teleconferences, video calls.
• Electronic purchase operations and capital movements.
• Data transmission , email and share resources in real time.
• Transmission stream stored media content.
• Satellite exploration and other surveillance and military recognition technologies.

Disadvantages of a computer network

The weak side of a computer network has to do with cyber attacks, which violate the confidentiality of information and can lead to dangerous activities.

We talk about both malicious software ( viruses , adware, etc.) or cyberterrorists (hackers), whose attacks can cause loss of information (and therefore capital), privacy violations or damage to equipment and software. The world of networks is diverse and complex.

Examples of computer networks

Here are some specific examples of computer networks:

• A home network . Like the WiFi networks that anyone can install in their own home, in order to serve a couple of computers and / or cell phones. Its scope will barely exceed the margins of the department.
• The serial network of a call center . The so-called cybercafes or call centers were very popular with Internet penetration, before the arrival of Smartphones . They contain a series of computers that share their Internet connection, and are available for public use, framed in an internal network, whose head was the computer of the local manager.
• A university campus network . Called CAN (Campus Area Network), they are actually MAN networks adapted to the various buildings and interests of the university community.
• Internet . The biggest WAN available today: communicating various technological devices over huge distances, from one side of the world to the other. This gigantic network involves computers everywhere, operating servers and workstations for millions.

Examples of LAN networks

1. A home network . Like the wireless (WiFi) that anyone can install at home to serve a couple of computers and cell phones. Its reach will hardly exceed the margins of the department .
2. A store network . Small branches of a business or store often have their own network , to provide Internet connection to their computers and, often, to customers.
3. An internal network of an office . In offices, an internal network (intranet) is often implemented that connects all workers’ computers , allowing them joint access to peripherals (such as the same printer) and sharing work folders or material of mutual interest.
4. A public network in a square . In many cities the public and free Internet program is implemented through wireless connection points with a range no greater than a few meters in a radius .
5. A serial network in a parlor . Internet cafes or phone booths are businesses that became very popular with the penetration of the Internet prior to the arrival of Smartphones . They used to contain a series of computers with Internet connection available for public use , but framed in an internal network whose control resided in the computer of the manager of the premises.

Examples of MAN networks

1. An inter-ministerial network . Many government agencies require joint work or share important data, which is why they are interconnected through a fiber optic network that allows them to be on the other side of the city and not lose contact .
2. A network between branches. Many stores and businesses are interconnected in the same city, allowing a user to search for a product in the closest branch and, if it is not available, they can request it at another location further away or, in the worst case, direct the customer to the book in some other branch .
3. A network of a local ISP. Companies that sell local Internet access to people are called ISP ( Internet Service Provider ) . They do it precisely through various MAN networks, each of which manages the resources of a city or a locality to the various clients requesting it, that is, to each particular LAN.
4. A network on a university campus . Also called CAN ( Campus Area Network ), they are actually a MAN adapted to all the various buildings that make up a university city , and which may well be separated from each other by considerable distances.
5. A municipal government network . The data of a municipality or mayoralty is often shared in a network that concerns only those who live in it, since citizens of other localities will have their own. Thus, the payment of municipal taxes or bureaucratic procedures can be carried out more effectively .

Examples of WAN networks

1. The Internet: The best example of a WAN available is the Internet, capable of communicating various technological devices over enormous distances, even from one side of the world to the other. It is a gigantic network that has often been compared to an ocean, a superhighway, or an entire universe .
2. A national banking network:. Bank branches in a country are managed through a vast network and in connection with other banks and even with banks abroad. Each of these networks is a WAN that allows a user to withdraw money at an ATM on the other side of the country, or even in a different country .
3. Transnational business networks: Large business franchises that have a presence in different countries around the world, keep their workers communicated through an exclusive WAN of the company, so that they can exchange information and stay in permanent contact despite being in different countries .
4. Military satellite networks: The various defense and military surveillance networks that concern satellites, ships, airplanes and other vehicles scattered around the world, are necessarily wide-ranging and enormous, so they could only be of the WAN type .
5. Pay TV networks: Cable or satellite television and other entertainment and information services based on new technologies necessarily use a WAN network to connect their subscribers in various countries in various regions of the continent .