Client Server Model Essay

The Internet is based on a client-server model, where every day, millions and millions of computers are accessing thousands and thousands of servers. Many of the things we use our computers for today make use of this model, from web browsing to electronic mail. Over the years, competing models of networking emerged to compete with the client-server model. The peer-to-peer model has been a prominent competitor with vast differences. Mainframe architecture, from which the client-server evolved, still has a place in business today and the two compete on the back-end. This essay will discuss the client-server model, and compare it with other models it has been in competition with – the peer-to-peer model, and mainframe architecture. THE CLIENT-SERVER MODEL The client-server model is a distributed application structure that involves tasks being partitioned between servers, which are responsible for providing services or resources, and clients, which do the service requesting. Clients are usually a personal computer, and recently have been expanded to include mobile devices. The client does not share its own resources with the server, but it does initiate requests for services or content from the server. Client/server systems evolved from mainframe architecture when it was realized that personal computers had become more self-sufficient, both in data storage and processing power, not to mention more affordable. Personal computers were able to offer just about all the features that were offered on mainframe computers. At the outset, the client-server model existed as a two-tier architecture – a client and an application server, in which the client acts as a presentation layer that communicates with the server, a centralized data layer. Most client-server architectures are two-tier. In fact, most Internet applications are simple two-tier applications. This includes Email (SMTP), web browsing (HTTP), and file transfer applications (FTP). Each application for these protocols presents a graphical user interface (GUI) that helps a user interact with the server. A third tier was later added, as a functionality layer to exist between the presentation layer and the data layer. This layer, referred to as the application tier, was added to manage requests made from the client. This is where scripts are performed before information is requested from the data storage layer. In terms of our class, this is where our ASP code would be executed to query the Northwind database. As mentioned above, the client-server model is the most commonly used model with regards to the Internet. There are many advantages to using this model over others, but at the same time, there are some disadvantages to using the model. CLIENT-SERVER MODEL ADVANTAGES The client-server model has several advantages. The first and foremost is centralization. Having one central server makes it much easier to manage a network. For instance, having a central server that stores a network’s user names and passwords, as well as each user’s privilege rights makes it much easier than having to manually configure the rights on each computer on the network. Without the distribution of resources that client-server architecture allows, if a network contained multiple servers, each one would need to be updated individually with user login and privilege information. System updates can also be made to many computers at once from any computer on the network, instead of having to do so one by one. Scheduled backups made by the server make it easier to recover lost files. Leaving each individual client on a network the responsibility of backing up its own computer can prove to be complicated and dangerous. Centralization also allows security measures to be distributed throughout the network by the server, making it safer than a peer-to-peer network. It also means that users on a network using the client-server model can use shared printers and storage space, which can cut down on costs. Having central storage on the server is also a good way for client computers to save hard drive space and prevent redundancy. The second advantage is its ease of scalability. Adding several computers in a client-server model is much easier than doing so in a peer-to-peer model. This is because an administrator can easily install any necessary applications to computers added to the network from the server. Making any additions to a client-server network will not cause any interruptions to other clients on the network. Having a client-server setup also ensures safer remote accessibility. CLIENT-SERVER MODEL DISADVANTAGES Although the client-server model has many advantages, it does come with some disadvantages. Though some costs can be cut using a client-server-model as mentioned above, the server must be robust and powerful enough to support the client computers on its network. Because of this, there is a large cost that goes along with operating the servers. Another disadvantage that adds cost is the maintenance needed for the servers. Most client-server networks need at least a network administrator to oversee and maintain the network. This is something that is not needed in a peer-to-peer network, since there is no centralized server, and each client node is responsible for maintaining itself. Because a client-server based network relies on a central server, each client in the network is reliant on the server to operate. If the server goes down for any reason, the network will not be able to function. To ensure that this doesn’t happen, many networks now employ backup servers, which of course, is an extra cost. Congestion is also a possible issue for networks using a client-server model. Again, since the centralized server is handling the brunt of traffic from clients on the network, if many client computers are using the network at the same time, it will slow down the server’s response.