Main Functions of Middleware - Essay Example

Middleware simply connects these applications and passes data between them by providing an interface for allowing client application programs to interact with server application programs. Current business trends require integration such as ERP, SCM, and CRM. Business to Business (B2B) communication needs will further accelerate this trend. The need for middleware stems from this increasing growth in the number of applications and in the customizations within those applications.

Middleware’s main function is to provide a standard way of translating between software from different vendors. ‘Network Computing’ categorizes it as:
- Client/Server Connectivity -Middleware manages message transfer between client and server, thus it enables client-server communication and insulates network changes from the clients.
- Platform Transparency - Using interfaces and APIs abstraction features, Middleware provides Platform Transparency. Client and server don't require to have intimate knowledge of each other in order to work together.
- RDBMS Support – Data access middleware provides transparency across different data storage formats. It will make different RDBMS look like the same RDBMS by providing multiple RDBMS support from both proprietary and standard APIs.
- Language Support - Middleware often provides transparency across different SQL database dialects.
- Advance applications - New enterprise applications harness Middleware technology for Single System Login, Enhanced Security, Location Transparency, and Database and Application Oriented Services however they are not very common.

There are a small number of different kinds of middleware that have been developed. Based on the uses they can be categorized into the following categories:
- Remote Procedure Call (RPC) - Remote procedure call Middleware extends the procedure call interface familiar to all programmers offering the abstraction of being able to invoke a procedure whose body is across a network.
- Message-Oriented Middleware (MOM) - Message-Oriented Middleware provides the abstraction of a message queue that is accessible across a network. They are based on SOAP.
- Distributed Object Middleware (DOM) – DOM such as DCOM and CORBA gives all the advantages of OOPS such as encapsulation and inheritance. It provides the abstraction of an object that is remote yet whose methods can be invoked just like those of an object in the same address space as the caller. are such examples.
- Direct data access (DDA) for accessing databases directly as opposed to going through an application to get the information.

Middleware offers many technical benefits. Current enterprise applications involve multiple applications interacting with the same application. Instead of providing different APIs for the different client applications, we can put a Middleware with a single set of APIs for each application. This can significantly simplify communication. Also, the Middleware can be used to handle different services such as checking the data for integrity, reconciling the data with other applications, data splitting, and formatting so that we don't have to rewrite those services again and again for different applications. Middleware may have the capability to hold this data for a while so that it can be served to other applications which need it. Thus, it can introduce a type of persistence in the system. However, there are some limitations of the Middleware systems. Some of them are:
- Non-standard interfaces - Traditional middleware systems and tools suffer from a lack of standardization: they are not compatible. Thus, it is very expensive to build integrated distributed systems across different middleware platforms.
- Lack of trust – When Middleware is used for Web Services the internal “API” of a company is exposed to any client on the Internet. In such a scenario it becomes very difficult to decide whether the clients can be trusted
- Problem with scaling – As the Middleware are centralized system, Point to-Point integration does not scale. Such Point to Point Middleware solutions are expensive and do not scale well with the number of systems to be integrated
- Performance and speed – Interactions inside an extended enterprise or across organizational boundaries may be slow and should be handled asynchronously.

In this paper, we have discussed the main function of Middleware such as role, usage, cost & limitations, platforms, type, software and etc. But the question is: “What does the future hold?” Consolidation and convergence of vendors and standards will continue. With the increasing heterogeneity, the importance of Web services and services will soar with the increasing abilities of XML and SOAP.