What is a computer network?

A computer network is a collection of devices (computers, servers, phones, network equipment) connected by data transmission channels that let these devices exchange information and share resources.

If you want a phrasing that sounds ideal in an interview:

A computer network is a system of nodes and communication channels that enables data transfer between devices using a set of network protocols.

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#Key elements of a computer network

#1. Nodes

These are devices that participate in the network:

• computers
• servers
• routers, switches
• printers
• phones, IoT devices

A node can be a source, a destination, or an intermediate device.

#2. Communication channels

What data is transmitted over:

• cable (twisted pair, coaxial, fiber)
• Wi-Fi / radio / mobile communication
• VPN tunnels

#3. Protocols

A set of rules for transmitting data. The main stack is TCP/IP.

Protocols define:

• how packets are formed
• where they go
• what to do on errors
• how a connection is established

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#What a computer network lets you do

1. Exchange data - sending packets, messages, files, requests.
2. Share resources:

• printers
• disk storage
• internet connection
• computing power

3. Organize communication:

• VoIP, video calls
• online games
• streaming

4. Provide centralized management:

• domain policies (Active Directory)
• device monitoring
• centralized updates

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#Main types of computer networks

#LAN (Local Area Network) - local network

Scope: office, apartment, building. High speed, low latency.

#WAN (Wide Area Network) - global network

Connects cities, countries. The internet is the largest WAN.

#MAN (Metropolitan Area Network) - city scale

Example: a provider's network between districts of a city.

#WLAN - wireless local network

For example, Wi-Fi.

#PAN - personal network

Bluetooth headphones, a smartphone, a smartwatch.

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#Why a computer network is needed

Without a network, devices could not:

• access the internet
• interact with each other
• work within a corporate infrastructure
• exchange information in real time

Modern services (mail, cloud, messengers, games, video conferencing) exist only thanks to networks.

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#How to explain this in an interview: an example of a correct answer

"A computer network is a set of devices connected by communication channels and using protocols to transmit data. It lets nodes exchange information and share resources. Networks can be local, global, or personal, and their work is built on the TCP/IP stack and routing."

Short, precise, no filler.

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#Cheat sheet (5 seconds before the interview)

• A computer network is a system of devices + communication channels + protocols.
• The goal is data exchange and shared use of resources.
• Main types: LAN, WAN, MAN, WLAN, PAN.
• The basis of operation is protocols (TCP/IP), addressing, and routing.