Introduction to Client-Server Networks

The client-server network is a computer networking model where at least one of the computers (called server) is used to “serve” other computers (called clients). The server is a specialized and powerful computer that manages the network resources and offers services to other computers in the network.

All other computer devices in the network other than the server are known as clients.

There have been different kinds of models that have developed over the years and the dominating model amongst them is the client-server networking model.

This model utilizes both client hardware devices and servers. Each of them has particular functions. This model can be used on the internet as well as local area networks (LANs).

The client-server network model is a type of distributed computing model.

Another prevalent distributed computing model which often comes in the discussion along with the client-server model is the peer-to-peer network.

But both of them have striking differences which we shall look at in the later part of the article.

In this article, we will be getting an overview of what a client-server network is, some examples, how they communicate, the advantages and disadvantages of such a model and difference with peer-to-peer architecture. Let’s begin!

What is meant by the client-server system?

A client is said to be any process which asks or requests for particular services from server processes. The server is the process which provides them with the requested services.

The client-server network is usually designed for end-users (clients) to access different resources like files, music, or other services from a central computer (server).

The server is responsible for maintaining all the resources like files, directories, applications, etc. Besides network management, it also deals with significant operations like security.

Whenever any client wants to access any of its services, it has to first seek permission from the server by sending it a request.

This concept became popular from the late 1980s when several applications shifted from centralized minicomputers and mainframes to computer networks of personal computers.

Most LANs are based on client-server relationship.

Client-Server hardware

Usually, the client devices are PCs with installed network software applications for requesting and receiving information over the network. Both mobiles, as well as desktop computers, can be referred to as clients.

Generally, the server stores files and databases, and even includes highly complex applications like websites.

In comparison to clients, server devices have higher-powered central processors, more memory and larger disk drives.

How do the client and server communicate?

Clients and servers follow the request-response messaging pattern for exchanging messages where the client sends a request and server responds to it.

For this inter-process communication, the devices should have a common language with rules defined in the communication protocol.

A server can support many clients. Also, several servers can be networked together in a server pool for dealing with augmented processing loads with an increase in the number of clients.

The client and server can be two separate units of hardware, or a single device can also function as both client and server under certain circumstances.

Also, a system working as a server for one application can act as a client to other servers for different applications.

The client-server protocols operate in the application layer. Server can

sometimes incorporate an application program interface (API) for facilitating parsing and cross-platform data exchange.

What are the advantages and disadvantages of the client-server network?

The client-server network is one of the most dominating computing models that has developed over the years. Let us look at its benefits at first.

Advantages

• Here, the resources are centralized. This aids in easier network management and is also cost-effective. Having centralized servers keeps things at one place and helps in quicker solving of problems.
• Because of central administration, security is highly bolstered in this type of network. For accessing the network, the user has to provide credentials like username and password. If they are invalid, access is denied, else allowed if matched.
• Using dedicated servers improves the entire system performance. Also, it increases the speed of sharing resources.
• Intranet capability, internet monitoring, centralized backup, etc are some other significant advantages. In a small network, one single server can handle all these services, whereas, in medium or large networks, many servers can perform these tasks, each with specified purposes.

Disadvantages

Just like every other thing in the world, even the client-server network model has certain drawbacks.

• A dedicated network administrator is necessary.
• Network operating system, required for managing different clients, is costly.
• Specialized servers with large memory and secondary storage increase the costs.
• There is a risk of system overload in this model. If several clients try to reach the shared network at the same time, then there is a high chance of failure or slow down in connection.
• If a server is turned OFF, then most of the resources become unavailable on the network. The clients are then disabled from accessing information, and they land in trouble.

Client-server network vs. peer-to-peer network

Both client-server network and peer-to-peer network are types of distributed computing. But both of them widely differ from each other.

Do you want to know how? Review the following table to get details

Can you state some examples of the client-server model?

Well, examples of the server include mail server, file server, and web server. They offer resources to clients such as desktop computers, laptop, smartphones, and tablets.

When a client requests a service to a server, the latter can either accept or reject it. If the request is accepted, the server establishes and maintains a connection with the client over a particular protocol.

Lets see some examples

For example, an email client may initiate an SMTP connection to a mail server for sending a message.

Then, the SMTP application on the mail server will further request authentication from the client, like the email address and password, which when match an account on the mail server, the server sends the email to the intended receiver.

Also, online multiplayer gaming incorporates the client-server model. One famous example is the Blizzard’s Battle.net service, which hosts online games for World of Warcraft, StarCraft, Overwatch, etc.

When players open a Blizzard application, the game client connects to a Battle.net server automatically.

Once logged in to Battle.net, the players can view who else is online, chat with them, and play matches with or against other players.

Conclusion

The client-server network model is a type of distributed application design where servers are the service providers, and the clients are the service requesters. They can be on different hardware units or can be in the same machine.

The client-server feature highlights the relations of cooperating programs in any application. The clients request for a service from a server, which the latter may accept or reject.

If approved, a connection is established between them and then they can communicate via it.

The resources in the client-server network are centralized which enhances greater network management and also strengthens the security of the network.

Dedicated servers also improve system performance. However, such networks are usually expensive.

There is a threat of system overload in this model. Also, if the server is ever turned off, it makes the resources unavailable to the clients and can cause massive damage to businesses, create problems for different users, etc.

Therefore, the server must always be on, or there must be more than one server with tasks distributed amongst them to handle client requests.