Client-server architecture is a type of distributed system that consists of clients and servers. Server is responsible for hosting, managing, and delivering services to clients. Here clients are connected to the server and communicate with it over the internet using a computer network. So when a client needs a service, it sends a request to the server, which processes the request and sends a response back to the client.
Let's consider an example of client-server architecture using a service like Gmail. Here, the client can be the web browser or email interface, which interacts with the email service. The client can send HTTP requests to the mail server for actions like fetching emails, composing new emails, or deleting messages and displaying the received data (emails, attachments, etc.). Here, the mail server handles the storage, retrieval, and manipulation of emails and user data.
When you send an email, the client side sends a request to the mail server, which processes the request and stores the email in your account. Similarly, when you request to view your inbox, the client sends a request to the server, which retrieves the relevant emails and sends them back to the client for display. So, client-server architecture is a good example of the separation of concerns: the server handles the heavy data processing, while the client focuses on providing a user-friendly interface.
A complex client-server architecture consists of several components. At the basic level, there are four important components: client, load balancer, servers, and network protocols.
The data flow in a client-server architecture is unidirectional and forms a cycle. It begins when a client requests data from the server, and the server processes the request by querying a database for relevant data. The database then returns the data to the server, which processes it and sends it back to the client. Clients cannot communicate directly with each other.
Here is a simple example of how a client (browser) interacts with servers in a client-server architecture:
There are several types of client-server architectures, each with its own advantages and disadvantages.
There are only two components in a two-tier architecture: client and server. Here client directly communicates with the server. So this architecture is simple and easy to set up, which makes it suitable for small applications. As the application grows in size and complexity, it will be less efficient and take longer to process requests.
To understand this better, you can think client as a customer who goes to a fast-food restaurant and directly places an order with the cook (server). The cook then prepares and serves the food to the customer. So this process can be less efficient if there are many customers or if the customer wants a more complex meal.
There are three components in a three-tier architecture: client, application server, and database server. Here client sends a request to the application server, application server processes the request and communicates with the database server to retrieve or update the data. So this architecture can work well for medium to large-scale applications and provides better scalability and fault tolerance.
To understand better, you can think of the client as a customer who goes to a restaurant and places an order with a waiter (application server). The waiter then communicates with the kitchen staff (database server) to prepare the food. This will help the restaurant system to serve efficiently because multiple waiters and kitchen staff can be added to serve more customers.
There can be multiple tiers in N-tier architecture: presentation, application, data tiers, etc. Each tier is responsible for a specific function, and they communicate with each other to perform the required tasks. So this architecture is suitable for large and complex applications because it can provide better scalability and fault tolerance than the 2-tier and 3-tier architectures.
To understand better, you can think client as a customer who visits a restaurant with a well-organized hierarchy of staff. Each staff has a specific role, such as host (presentation), waiter (application), and kitchen staff (data tier). The host greets the customer and shows them to their table, the waiter takes their order and communicates with the kitchen staff to prepare the food, and the kitchen staff delivers the food to the table.
Here are some major differences between peer-to-peer and client-server architecture:
The client-server architecture has several benefits:
There are some drawbacks:
We hope you enjoyed this blog on client-server architecture. We covered the fundamental concept behind it, how it works, and how it can be an efficient way of interaction. We hope you found it helpful. If you have any thoughts or feedback, please share them with us in the comments below. Thanks for reading!
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