Message-oriented middleware (MOM) provides rules-based messaging routing capabilities. In addition, MOM includes message broker technology. Messaging brokers enable request and reply constructs to be handled asynchronously, which supports the guaranteed delivery and integrity of messages between applications and components.

First generation MOM

IBM MQSeries had emerged as the de facto standard in the messaging middleware market, owning over half of the market in first generation MOM. However, MQSeries is based on a first generation, asynchronous, broker-centric design.

We have now seen the next generation of message-oriented middleware, which extensively uses the publish and subscribe model for message and application brokering. The publish and subscribe paradigm's primary strength lies in allowing applications and components to communicate and exchange information without too many established connection dependencies.
Transparency in publish and subscribe
The communicating component's physical location and identity (barring security implications) are transparent to one another. This is similar to a person "subscribing" to the New York Times. When the paper is "published" it appears at the subscriber's doorstep. The publisher of the New York Times does not need to know the identity of the subscriber. Likewise, the subscriber does not need to know where the New York Times publisher resides. Both parties have their service fulfilled without knowing the routing involved: The New York Times distributes and gets paid, and the subscriber receives and reads.
Advantages of publish and subscribe
The publish and subscribe model offers flexibility not found in earlier generation message-oriented middleware which typically used a single static broker. In the publish and subscribe model, publishers (message stores) and subscribers (message users) may be deployed dynamically and in various numbers.

Message Oriented Middleware Vendors and Tools
Publish and subscribe also allows for highly flexible, yet reliable, security schemas.
For more information on vendors and tools associated with message-oriented middleware, click on the Search button located at the top of the page.
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