Web client_server enterprise architecture

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Client-server architecture: What's the ideal strategy?

Client-server architectures exist to provide organizations flexible and robust infrastructures that, depending on how they are designed, can cater to specific business needs. A client-server environment very simply involves a client computer that calls for information from a base or server that has the ability to process the request and send back a response. This response will be either positive or negative and often a positive response can have multiple variations. Client software needs to be able to present these responses in the appropriate fashion to present to the user.

Many aspects of a business including its size, its focus and the tasks required of it, can help determine the ideal client/sever architecture to implement. Below are descriptions and key advantages and disadvantages of different client/server environments, as well as an analysis of the debated strategies used in a client-server/Web-server environment.

Host-client. In a typical Host-client application, often referred to as "mainframe" architecture, most users find themselves on a "dumb" terminal while strapped to a host computer. This architecture although effective, often is expensive, difficult to maintain and does not easily support graphical user interfaces. Flexibility and change is not an option without extensive cost considerations or careful planning.
Pro: Easy client installation, reliable
Con: Expensive, high maintenance, older technology

Basic client-server. Basic client-server architecture allows a client to send a request to a server through a query, thereby reducing network traffic. The server then queues and processes the request by interpreting; analyzing and "serving up" the information back to the client. The client application then has the ability to present this information to the user via a graphical user interface or if it is preferred, through a host terminal. This process allows for a multiuser environment using a shared data source.
Pro: Ideal for small businesses, shared data environment
Con: Software deployment, software control, poor performance

Client-server 2-tier. The 2-tier architecture generally describes a client-server environment with additional processing being provided by a database-management server. The main advantage of this set-up is that heavy processing on the client side is minimized and therefore, less client-side software is required. In this case, since many changes are made on the server itself, costly deployment costs can be avoided, especially in a larger organization.
Pro: Ideal for large business, inexpensive workstation software
Con: Expensive server

Client-server multitier. With the multitier architecture, often called the 3-tier architecture, processing can be centralized in at the middle tier. In larger enterprise level environments, many database servers may be storing information for a variety of application and business requirements. In these environments, the middle tier will easily support each different database server by using shared and reusable rules and models. These rules can be changed from a central location, providing standardization and organization for the corporation.
Pro: Performance balancing, rules sharing, organization
Con: Software costs, multiple vendors, complicated infrastructure

Client-server multitier distributed. A variety of other configurations exist that also qualify as client-server. The distributed server architecture can be used to provide localized processing of data based on information sent from a central processing server. This allows the local servers to process data, content and message as a subset of the entire enterprise while consolidating the interactions with the central system.
Pro: Performance balancing, lower data transmission, good for
multifaceted businesses
Con: Expensive, additional servers, data integrity, complex infrastructure

Client-server/Web-server. The Internet has provided another definition of client-server architecture. A Web server can be viewed as a second-tier, middle-tier, or other tier. As a request comes from the browser (client) the Web server has the ability to forward the request to a database server. At this point, the Web server actually behaves as a client. Another form of Web serving occurs when the Web server sends a tiny application to the client that can be run on the browser. This offers additional control and flexibility. Content management is mostly associated with Web servers and is an integral part of providing Web sites with video, pictures and other media content.
Pro: Easiest client deployment, good for e-businesses
Con: Expensive, multiple vendors, equipment

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