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Client-Server Architecture

Client-server architecture, a model prevalent in computer networks, involves a central server, also referred to as the host computer, acting as the hub for multiple clients, or remote processors, that initiate service requests.

Using the interface provided by client computers, users can request services from the server and observe the corresponding responses. Servers await client requests before providing replies.

A client, any machine sending a request to the server, can be illustrated when visiting a website. In this scenario, the user is the client making the request.

In client-server architecture, a central server (or host computer) serves as the focal point for various clients (or distant processors), while the server itself processes and responds to client requests. In the website example, the client requests the webpage, and the server delivers it in response.

Operation of the Client-Server System

When a client seeks data from a server, it first uses the Domain Name System (DNS) to obtain the server's IP address. The DNS server provides the IP address.

The client's request to that IP address includes the port number assigned to the specific application. The server responds when the client sends a request to that IP address with the designated port number. Upon receiving the return message, the client's program identifies the port number and processes the response packet.

In this interaction, clients and servers communicate at a high level through HTTP packets.

Client-Server Architecture Types

The forms of client-server architecture vary based on the business logic handling requests:

  • One-Tier Structure
  • Two-Tier Structure
  • Three-Tier Structure

Single-Tier Architecture

In a one-tier structure, all application-related components are bundled into a single package. This includes logic related to the database, business logic, user interface, and database, all integrated into one entity.

While a one-tier architecture offers numerous services, managing it can be challenging, primarily due to data volatility and repeated work. The architecture comprises presentation, data, and business layers, with specialized software integrating these layers.


Two-Tier Structure

Similar to one-tier, a two-tier structure combines all application components into a single tier. It provides dependable services but faces challenges in managing data volatility. The presentation, data, and business layers are integrated by specialized software, with data typically stored on shared storage or local systems.


Three-Tier Structure

A three-tier system introduces middleware between the client and server, offering enhanced security compared to the two-tier system. Three-tier architectures consist of display, application, and database layers. Servers and middleware control application and database layers, while client devices handle the presentation layer.


Benefits of the Client-Server Model

Simple File Management: Files are centrally stored, simplifying management.

Easy to Use: Accessible from any platform and location.

Server Scalability: Easily scalable with high flexibility.

Centralized Control: Centralized administration enhances control.

Security: Strong data protection due to centralized architecture.


Cloud Processing

Cloud computing, widely utilized by businesses and consumers, involves pay-as-you-go access to IT resources over the Internet. Cloud services, such as Box, Dropbox, OneDrive, and Google Drive, offer data storage.


Model for Cloud Computing Services

Cloud computing comprises platform-as-a-service (PaaS), infrastructure-as-a-service (IaaS), and software-as-a-service (SaaS). IaaS provides internet access to IT infrastructure, PaaS offers software and hardware to end-users, and SaaS enables subscription-based access to software without local installation.

How Safe Is Cloud Computing?

Cloud security is crucial for protecting digital assets and data stored on cloud-based services. Security measures include firewall services, VPNs, security tokens, two-factor authentication (2FA), and data encryption.

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