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Concept

A computer network consists of two or more computers connected together, either by cable (wired) or WiFi (wireless), for the purpose of transmitting, exchanging or sharing data and resources. A computer network is built using hardware (e.g. routers, switches, access points and cables) and software (e.g. operating systems or business applications).

Types of computer networks

LAN (local area network): A LAN connects computers over a relatively short distance, allowing them to share data, files and resources. Computers in an office building, school or hospital. LANs are typically privately owned and managed.

WLAN (wireless local area network): A WLAN is the same as a LAN, but connections between network devices are made wirelessly.

WAN (wide area network): As the name implies, a WAN connects computers over a wide area, for example from region to region or even continent to continent. The Internet is the largest WAN.

MAN (metropolitan area network): MANs are typically larger than LANs, but smaller than WANs. MANs are typically owned and managed by cities and government entities.

PAN (personal area network): A PAN serves a single person. For example, if you have an iPhone and a Mac, chances are you have set up a PAN that shares and syncs content - text messages, emails, photos, etc.

SAN (storage area network): A SAN is a specialized network that provides access to block-level storage - shared network or cloud storage - that, to the user, looks and functions like a storage unit physically attached to a computer.

CAN (campus area network): A CAN is also known as a corporate area network. A CAN is larger than a LAN but smaller than a WAN. CANs serve sites such as schools, universities and corporate campuses.

VPN (virtual private network): A VPN is a secure point-to-point connection between two network endpoints (see "Nodes" below). A VPN establishes an encrypted channel that keeps the user's identity and login credentials, as well as transferred data, inaccessible to hackers.

common terms

  • IP Address Is a unique number assigned to every device connected to a network that uses the Internet Protocol for communication. Each IP address identifies the device’s host network and the location of the device on the host network. When one device sends data to another, the data includes a ‘header’ that includes the IP address of the sending device and the IP address of the destination device.

  • Nodes: A node is a connection point inside a network that can receive, send, create, or store data. Each node requires you to provide some form of identification to receive access, like an IP address. A few examples of nodes include computers, printers, modems, bridges, and switches. A node is essentially any network device that can recognize, process, and transmit information to any other network node.

  • Routers: A router is a physical or virtual device that sends information contained in data packets between networks. Routers analyze data within the packets to determine the best way for the information to reach its ultimate destination. Routers forward data packets until they reach their destination node.

  • Switches: A switch is a device that connects other devices and manages node-to-node communication within a network, ensuring data packets reach their ultimate destination. While a router sends information between networks, a switch sends information between nodes in a single network. When discussing computer networks, ‘switching’ refers to how data is transferred between devices in a network. The three main types of switching are as follows:

  • Circuit switching, which establishes a dedicated communication path between nodes in a network. This dedicated path assures the full bandwidth is available during the transmission, meaning no other traffic can travel along that path.

  • Packet switching involves breaking down data into independent components called packets which, because of their small size, make fewer demands on the network. The packets travel through the network to their end destination.

  • Message switching sends a message in its entirety from the source node, traveling from switch to switch until it reaches its destination node.

  • Ports: A port identifies a specific connection between network devices. Each port is identified by a number. If you think of an IP address as comparable to the address of a hotel, then ports are the suites or room numbers within that hotel. Computers use port numbers to determine which application, service, or process should receive specific messages.

  • Network cable types: The most common network cable types are Ethernet twisted pair, coaxial, and fiber optic. The choice of cable type depends on the size of the network, the arrangement of network elements, and the physical distance between devices.