Client/Server Architecture

Client/Server architecture is a computing model that divides the responsibilities and tasks of a system into two primary components: the client and the server.

• This architectural approach is widely used in networked systems, including web applications, databases, and other distributed computing environments.

• The client and server communicate over a network, such as the internet, and work together to fulfill the requirements of a particular application or service.

Here are the key components and characteristics of client/server architecture:

Client:

The client is the end-user device or application that initiates requests to the server. It can be a personal computer, smartphone, tablet, or any device with a user interface.

Responsibilities:

• User Interface: The client is responsible for presenting information to the user and receiving user inputs.
• Request Generation: The client generates requests for services or resources and sends them to the server.
• Data Presentation: It processes and displays the data received from the server.

Server:

The server is a powerful computer or system responsible for processing requests from clients, managing resources, and providing services.

Responsibilities:

• Service Provision: The server provides services, processes requests, and manages resources based on the client’s requests.
• Data Processing: It performs computation, manipulation, or retrieval of data as requested by the clients.
• Resource Management: The server manages shared resources such as databases, files, or application logic.

Communication:

Request-Response Model: Communication between the client and server follows a request-response model. The client sends requests, and the server responds with the requested information or services.

Protocols: Standardized communication protocols, such as HTTP for web applications, are often used to facilitate communication between clients and servers.

Tiers of Client/Server architecture

Client/Server architecture can be categorized into different tiers based on the number of layers or components involved in the system.

The most common tier architectures are:

1-Tier Architecture:

In a one-tier architecture, also known as a single-tier architecture or monolithic architecture, all the components of an application are deployed on a single platform or machine. There is no separation between the user interface, application logic, and data storage; everything runs on the same system.

Advantages:

• Simplicity: One-tier architectures are easy to understand and set up.
• Low Overhead: There is minimal overhead associated with communication between different layers or components.

Disadvantages:

• Lack of Modularity: Since everything is tightly integrated, changes or updates to one component may affect the entire application.
• Limited Scalability: It may be challenging to scale the application horizontally or distribute components across multiple systems.

2-Tier Architecture:

In a two-tier architecture, there are two primary components: the client and the server. This architecture is also known as client/server or client/server model.

• Client Tier:
  • The client tier is responsible for the user interface, user interactions, and presentation logic.
  • It generates requests for services or resources and sends them directly to the server.
  • The client tier can be a desktop application, a web browser, or any user-facing interface.
• Server Tier:
  • The server tier is responsible for processing requests, managing data, and providing services.
  • It handles the business logic, data processing, and interacts with databases or other backend systems.
  • The server tier can be a dedicated server or a cluster of servers.

Advantages:

• Simplicity and ease of implementation.
• Direct communication between the client and server.

Disadvantages:

• Limited scalability as both the client and server functionalities are closely coupled.
• Changes in one tier may affect the other, leading to tight coupling.

3-Tier Architecture:

In a three-tier architecture, an additional middle tier, known as the application server or middleware, is introduced between the client and the server. This architecture is often referred to as a three-tier model.

• Client Tier:
  • Same as in the two-tier model, responsible for the user interface and user interactions.
• Application Server (Middle Tier):
  • The middle tier is responsible for application logic and processing business rules.
  • It facilitates communication between the client and the server.
  • Common tasks include data validation, business rules enforcement, and additional processing before reaching the database.
• Server Tier:
  • Similar to the server tier in the two-tier model, responsible for data storage, retrieval, and management.
  • Handles database interactions and backend processing.

Advantages:

• Improved scalability and flexibility due to the separation of concerns.
• Changes in one tier have less impact on the others, promoting modularity.

Disadvantages:

• Increased complexity compared to two-tier architecture.
• Requires additional infrastructure for the application server.

Comparison: