A distributed computing model where tasks and workloads are partitioned between service providers (servers) and service requesters (clients).

Client-Server Architecture

Client-server architecture represents a fundamental paradigm in distributed computing that structures the relationship between computers in a network. This model divides computational workload and responsibilities between two distinct types of participants:

Core Components

Clients

End-user devices or applications that request services
Examples include web browsers, email clients, and mobile apps
Typically handle user interface and local processing
Maintain minimal state information

Servers

Dedicated machines or software that provide services
Manage system resources and control access
Examples include database servers, web servers, and email servers
Handle multiple client requests concurrently

Key Characteristics

Request-Response Pattern
- Clients initiate communication
- Servers respond to requests
- Protocol defines the rules of interaction
Distribution of Tasks
- Load balancing across multiple servers
- Scalability through server addition
- Resource sharing among multiple clients
Centralized Control
- Security management
- Data consistency
- Resource allocation

Common Architectures

Two-Tier Architecture

Direct client-to-server communication
Suitable for simple applications
Limited scalability

Three-Tier Architecture

Presentation tier (client)
Application tier (business logic)
Data tier (storage)
Enhanced modularity

N-Tier Architecture

Multiple specialized layers
Complex enterprise applications
Improved scalability

Advantages and Challenges

Benefits

Centralized resource management
Enhanced security control
Easier maintenance
Network efficiency

Challenges

Server bottlenecks
Single point of failure
Network dependency
Complex setup and maintenance

Modern Applications

The client-server model has evolved with:

Best Practices

Security Implementation
- Authentication mechanisms
- Encryption protocols
- Access control
Performance Optimization
- Caching strategies
- Connection pooling
- Resource optimization
Reliability Measures
- Failover systems
- Backup procedures
- High availability design

The client-server architecture continues to be a cornerstone of modern computing, adapting to new technologies while maintaining its fundamental principles of distributed responsibility and centralized management.