Message-oriented middleware

Message-oriented middleware (MOM) is software or hardware infrastructure supporting sending and receiving messages between distributed systems. MOM allows application modules to be distributed over heterogeneous platforms and reduces the complexity of developing applications that span multiple operating systems and network protocols. The middleware creates a distributed communications layer that insulates the application developer from the details of the various operating systems and network interfaces. APIs that extend across diverse platforms and networks are typically provided by MOM. This middleware layer allows software components (applications, Enterprise JavaBeans, servlets, and other components) that have been developed independently and that run on different networked platforms to interact with one another. Applications distributed on different network nodes use the application interface to communicate. In addition, by providing an administrative interface, this new, virtual system of interconnected applications can be made fault tolerant and secure. MOM provides software elements that reside in all communicating components of a client/server architecture and typically support asynchronous calls between the client and server applications. MOM reduces the involvement of application developers with the complexity of the master-slave nature of the client/server mechanism. Remote procedure call or RPC-based middleware Object request broker or ORB-based middleware Message-oriented middleware or MOM-based middleware All these models make it possible for one software component to affect the behavior of another component over a network. They are different in that RPC- and ORB-based middleware create systems of tightly coupled components, whereas MOM-based systems allow for a loose coupling of components. In an RPC- or ORB-based system, when one procedure calls another, it must wait for the called procedure to return before it can do anything else.