What is Client Server Architecture? Components, Types, Examples Explained

Networking involves data exchange and communication between different organisations and communities. Computer networks are evolving continuously, thanks to new technological innovations and advancements. Notable innovations include satellite internet, cloud, 5G technology, and blockchain, to name a few. 

Client-server architecture, also known as the client-server model, is one of the prime concepts of computer networks. Most networks today depend on this model for its higher efficiency and enhanced performance. 

What Is Client-Server Architecture

To explain client-server architecture simply, it is a computer network where clients request and receive services and files from a centralised server over a local internet connection. A client uses an application as an interface to connect to the server. Once the connection is established, the server processes operations and information storage. 

Introduction to Client-Server Model

This client-server model is a network application that breaks down workloads and tasks between servers and clients present on the same system or connected via a computer network. The architecture features multiple PCs, users’ workstations, or other devices, all connected to a central server via the internet or some other network connection. 

Once a client sends a request for data, the server accepts and processes the request and then sends data packets back to the user who sent the request. This model is also known as the network computing model or client-server network. 

Prime Components of Client-Server Architecture

The client-server architecture is similar to the request-response pattern and has a standard communication protocol defining communication rules and language. 

Here are the prime components of the client-server model:

• Workstations

Workstations are also termed client computers. Functioning as the servers’ subordinates, they request access to shared databases and files. A server asks the workstation for information and performs multiple tasks in the form of a central repository of programs, management policies, databases and files. Server-defined policies govern workstations. 

Operating systems primarily distinguish workstations and do not have security or administration policies, shared software or centralised databases. Workstations do not require CPU performance, memory areas or hard drive space, as they don’t need to handle requests from many computers. 

• Servers

Fast-processing devices, servers function as centralised repositories for policies, network files, databases and programmes. Most servers have robust memory and colossal storage space to handle multiple requests from several workstations simultaneously. 

In a client-server architecture, servers have different roles like a file server, mail server, domain controller and database server simultaneously. In a well-designed network, different duties are assigned to individual servers for enhanced performance. This server system simplifies backup and maintenance. 

• Networking devices

In a client-server model, networking devices connect servers and workstations. There are different networking devices, and each performs different functions across the network. Some of them are:

• Repeaters help in transmitting data from one device to the other.
• Hubs help in connecting a server to different workstations
• Bridges play a role in segmenting isolated networks. 

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Varieties of Client-Server Architecture

The service of the client-server model is spread across different tiers. Let us take a look:

• 1-tier architecture

In an all-in-one system, 1-tier architecture, a data logic system, a user interface environment, a marketing logic system and a client/server installation setting are all stored on a shared storage device or a single device. Though the wide range of services is trustworthy, managing this architecture is challenging. Because of the irregularity of data, there are duplicated efforts. 

One of the best examples of 1-tier architecture is a desktop application working offline, and data storage occurs on the same device it runs. 

• 2-tier architecture

The 2-tier design provides the best client/server environment. In the two-tier architecture, the user interface or UI is stored on the client system, while all the databases are saved on the server computer. Preserving both business and database logic is essential, whatever their storage destination. 

Responses are quick in the 2-tier architecture in DBMS as there is direct communication between client-server devices when the client places the order. 

• 3-tier architecture

In the 3-tier client-server architecture, the server and the client have middleware lying between them. When the client requests the server to fetch some information, the middleware receives the request, which is then forwarded to the server for further action. The exact same chain follows when the server responds to the client. 

The client machine handles the presentation layer management, the middleware handles the application layer management, and the server manages the database layer. 

• N-tier architecture

Also known as multi-tier architecture, it is a scaled form of two-tier and three-tier architecture. In this architecture, each function is located as an isolated layer, including application processing, presentation and data functionality management. 

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Functioning of Client-Server Architecture 

A client-server architecture has a client node and a server node. While the server functions as the producer, clients are considered consumers. A consumer sends a request to the server via a network. After processing, the consumer gets the final data per the submitted request. 

Here is an explanation of the functioning of the client-server model:

1. When a user puts in any file or website’s URL, the browser sends this request to the Domain Name System (DNS) server. 
2. The DNS server looks for the web server’s address.
3. The DNS server replies with the IP address of the web server. 
4. The browser sends HTTPS or HTTP requests to the IP address of the web server.
5. The server sends the required files for the website. 
6. The browser provides the files, and you have the website displayed. The rendering is completed with the help of a CSS interpreter, DOM interpreter and JS Engine.  

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The Objective of Client Server-Architecture 

Business organisations nowadays need a system to collect, process and act on corporate data efficiently. With the client-server network model in place, there is a higher level of processing, thus increasing the effectiveness of workgroup empowerment, workstation power, market-driven business, remote network management, etc. 

With client-server architecture, businesses get the exact framework for meeting the challenges of the fast-paced and ever-evolving IT world. 

Prominent Features of Client-Server Architecture

A client-server model has the following characteristics:

• A single computer server can provide multiple services simultaneously. However, each service will need a separate server program.
• Server and client machines need different and separate software and hardware resources from different vendors. 
• There is a requirement for a complete stack of protocols for both server and client computers. The transport protocol needs lower-layer protocols for receiving and sending individual messages. 
• Both server and client applications have direct interactions with the transport layer protocol. This process not only establishes communication but also helps entities in sending and receiving information. 

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Real-Time Instances of Client-Server Architecture

Here are some real-life client-server architecture examples:

• File servers

You use file servers to store files on various cloud-based services like Microsoft Office or Google Docs. Multiple clients can access these servers, which are centralised locations for file storage. 

• Web servers

These are high-performance servers hosting a plethora of different websites. Clients access web servers via the internet. 

• Email servers

Emails have become the primary mode of corporate communication owing to their speed and ease. Email servers help seamlessly receive and send emails between different parties. 

Understanding the Merits and Demerits of Client-Server Architecture

Advantages of the client-server model

• IT staff have access to changing server and client capacities separately.
• It is a centralised system where all controls and data remain in one place.
• It permits data recovery.
• It brings in high levels of efficiency, organisation and scalability.
• It is cost-efficient, particularly when it comes to maintenance. 
• It optimises performance with load-balancing. 
• The setup minimises the chances of data replication. 
• It permits various platforms to share resources.

Disadvantages of the client-server architecture

• In case a critical server goes down, consumers are at a loss.
• Data packets can be modified or spoofed during transmission.
• Initially costly to start up and implement.
• The server is vulnerable to DoS attacks, phishing and Man-in-the-Middle attacks.
• Users might be affected if the server has a virus or Trojan, as the network has linked servers and clients. 

Understanding 3-Tier Client-Server Architecture

The 3-tier client-server architecture comprises a User Interface layer (presentation tier), a Service layer (application tier) and a Database server (data tier). The client system controls the Presentation layer, the Application server handles the Application layer, and the Server system supervises the Database layer. 

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Peer-to-Peer Network vs Client Server Architecture

Peer-to-peer networks are also called P2P networks. These networks have a group of computers linked in a network, where peers are both the server and the client. Peers have the same permissions and responsibilities to work with the available data. However, the client-server model has defined groups of servers and users. 

Here are the differences between the two models:

Understanding the Difference Between System Architecture and Client-Server Architecture 

A conceptual model, system architecture specifies the behaviour and structure of a system. On the contrary, server architecture is a high-level structure which specifies the responses for meeting business and technical goals while maximising the quality of the software. 

The system architecture includes hardware and software parts and is used for designing a composite system. Server architecture considers business strategy, human dynamics, design, quality aspects, IT architecture, etc. 

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Conclusion

Networking is inevitable for business organisations to establish strategic alliances by exchanging data and communication. The client-server architecture lets multiple users update a shared database via a graphical user interface. This fundamental networking concept is used in many industries for improved data organisation, centralised file storage, and better management. 

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