What is a client-server network?

A client-server network is an interaction model in which one node (the server) provides resources or services, while other nodes (clients) request access to them.

A phrasing for the interview:

Client-server is an architecture where the server acts as the central node providing services, and clients are the consumers of those services. Interaction follows a request → response pattern.

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#How it works (simple logic)

1. The client sends a request (for example, to open a web page).
2. The server receives it, processes it, and performs the needed actions.
3. The server sends back a response (an HTML page, a file, data).

This is the request → response model.

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#Examples of client-server services

#1. Web services

• a browser (client)
• a web server (Nginx, Apache)

#2. Mail systems

• Outlook, Thunderbird → an SMTP/IMAP server

#3. File services

• an SMB client → a file server

#4. Databases

• an application → a DBMS (PostgreSQL, MySQL, MSSQL)

#5. Domain services

• a workstation → an AD Domain Controller

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#Roles in a client-server network

#Client

• initiates the request
• waits for a response
• does not store shared resources
• can be a PC, a browser, an application, a mobile device

#Server

• always "online"
• stores resources and manages them
• handles many requests
• has increased performance

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#Main characteristics of the client-server model

#1. Centralization

Resources are located in one place - on the server. This simplifies:

• management
• security
• backups
• scaling

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#2. Separation of roles

Client ≠ server. The client does not share its own resources but consumes the server's.

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#3. Easy to scale

You can:

• add servers,
• balance load,
• offload services by role (a DB server, a web server, a file server).

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#4. Increased security

Through the server you can:

• control access
• filter requests
• keep logs
• apply policies

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#Comparison with P2P (Peer-to-Peer)

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#Where the client-server model is used

Practically everywhere:

• the internet
• corporate networks
• cloud services
• authorization systems
• games with a central server

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#Ready answer for the interview

A client-server network is an architecture where the server provides services or resources, and clients request access to them. Interaction follows the request-response model. The server is a centralized, always-available node that handles many client requests; the client is the consumer of the service. Examples: web servers, file servers, databases, domain services.

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#Cheat sheet (5 seconds before the interview)

• Client-server = request → response.
• The server serves, the client consumes.
• Centralization, management, security.
• The main model of the internet and corporate networks.
• Contrasted with P2P.