Can message brokers deliver? - architecture for designing more efficient middleware - includes related glossary, data warehousing article - Technology Information

Software Magazine, June, 1996 by Julie Bort

Sabre uses both star and bus topologies for its message broker systems, says Beberstein. Bottlenecks on the hub are avoided by using a sufficiently sized message queue and by staying on the lookout for potential problems.

"We've got a very large queue on the disks, so it's not limited by memory. At peak periods we may build up, but as a general rule, they don't lock up. Plus everything gets mirrored to the log," says Beberstein.

Though message brokers offer significant cost savings because they operate more efficiently than other middleware, they do not eliminate the work of writing an interface, warns Gartner's Schulte. Still, because developers are writing interfaces between a broker and an application, those interfaces need only be written once.

"This is the dirty little secret of message brokers. There's no free lunch," says Schulte. "Every interface to every application has to be constructed. What it's doing is helping you translate them and reuse them."

This reuse, says analyst Johan Vinckier, partner at McKinsey International in Brussels, Belgium, provides competitive advantage. McKinsey, which specializes in business analysis, has identified message brokers as a key technology for large organizations. "We've seen a number of cases where companies were able to grab market share because they could get their systems up very quickly," says Vinckier. "[Message brokering] is an enabler and a money saver because of the timeline to deliver. If you want to bring in call centers and Internet applications, there's really no alternative. You need something that allows these applications to talk to one another."

Related article: What's in the Middle

Message: Any bit of code sent between applications. Usually includes some instruction for the receiving application.

Messaging: 1) The genre of middleware technology that passes messages, one-way and blind. Once the message is delivered, the middleware's job is done; it has no knowledge of the contents of the message. 2) A term used by some analysts to describe a message broker architecture.

Message broker: Middleware architecture that provides a one-to-many, many-to-one and many-to-many delivery system, thereby eliminating point-to-point "spaghetti" code. It works between existing middleware technologies, and relies on either a star or a bus topology for delivering messages. Said to be a more efficient message delivery system that's less expensive to create, because programmers need to write an interface to each application only once.

Messaging queuing: Messaging middleware that relies on a store-and-forward approach to delivering messages. Though message queuing software is one of the underlying technologies of a message broker, it is not -- as some vendors claim -- a broker itself.

Middleware: Allows inter-application communication, from simple replication, to the transformation of a message to guarantee a process is correct.

Message-oriented middleware (MOM): Technologies that combine message queuing and message passing in realtime.