When we talk about a computer network we mean two or more computers connected to each other, with the aim of processing, transmitting, exchanging and sharing data and resources.

There are different types of networks, created according to their extension and the needs they must satisfy:

• LAN (local area network) connects network nodes in a relatively short distance such as a school, a hospital and is usually privately owned and managed.
• MAN (metropolitan area network) are networks larger than LANs, it leads back to a city or government agency.
• WAN (wide area network) this network connects computers over a large area, such as from region to region or continent to continent. Internet is the largest example of a WAN in the world.
• WLAN (wireless local area network) it is a network similar to a LAN, but the connections between the devices are made wirelessly.
• PAN (personal area network) a network that meets the needs of a person, such as someone who owns an iPhone and a Mac and wants to share resources between these two devices.
• SAN (storage area network) is a network that allows access to a storage that can be cloud storage or a shared network that is used as a storage method.
• CAN (campus area network) it is also known as a corporate area network and is larger than a LAN but smaller than a WAN. Typically used for college, university or corporate campuses.
• VPN (virtual private network) it is a secure connection, between two network endpoints. It is an encrypted channel that through login credentials allows access to data and resources and is inaccessible to hackers.

A computer network consists of nodes such as computers, switches, and routers that use fiber optic cables or wireless signals to share and communicate information. The operation of the network is marked by protocols (IP Internet Protocol) which are strings of numbers, through which the nodes exchange and receive information.

With routers, which are virtual or physical devices, information is analyzed and the best way to reach the final destination is determined. Switches connect devices to each other and manage communications between network nodes.

A network must be secure to protect the data that is transmitted and this can be guaranteed by the use of protections (Cybersecurity) such as firewalls which are devices that monitor network traffic and prevent access to some points of the network itself on the basis to the established safety rules. Other security measures can be authentication by ID and password, keep software and hardware updates always regular in order to be ready to react to external threats. The security process is always continuously updated for the evolution of network threats that exist.