Client vs. Server: Understanding the Key Differences

This article compares clients and servers, highlighting their key differences. It also introduces the basic client-server architecture model and explains the roles of each component.

Role of Client and Server

Client: A computing device that requests services. This includes desktops, laptops, smartphones, tablets, and even software programs that interact with servers.

Server: A computing device that offers or provides services. Servers can be large, powerful computers, but even a desktop PC can function as a server.

Client-Server Architecture Model (Internet Based)

The figure below illustrates an internet-based client-server architecture model.

Client Server Architecture

• Examples of applications using client-server architecture include the World Wide Web (WWW), email, and network printing.
• Different types of servers exist, such as web servers and file servers.
  • A web server serves web pages to requesting clients.
  • A file server delivers files to clients.
• Different protocols are used for communication between clients and servers.
  • Web servers commonly use HTTP/HTTPS.
  • File servers often use FTP/TFTP.

Other essential servers in internet architecture include DHCP and DNS servers.

• DHCP (Dynamic Host Configuration Protocol): Clients use DHCP to obtain IP addresses dynamically.
• DNS (Domain Name System): When you enter a website’s domain name (e.g., google.com) in your browser (Chrome, Firefox, etc.), DNS converts that name into a suitable IP address, allowing you to visit the site.

Client-Server Architecture Model: Different Modes

The figure below depicts client-server architecture in two different modes:

Client Server versus peer-to-peer architecture

There are various architecture types based on the client-server model, including distributed and peer-to-peer architectures.

Distributed Architecture

• In a distributed architecture, one or more dedicated machines function solely as servers, while all other machines are clients.
• Clients communicate through the server in this scenario.
• The client initiates the communication.
• The client sends a request to the server.
• The server replies or performs a service.

Peer-to-Peer Architecture

• In peer-to-peer architecture, each host or instance of an application program can function as both a client and a server simultaneously.
• Each peer has equivalent responsibilities and status.
• Any participant can initiate communication.
• Any device can generate a request.
• Any device can provide a response.