Integration Technologies - Guide to Cloud Computing for Business and Technology Managers - page 119

management. With this configuration, a low-bandwidth system may
still attain acceptable performance, whereas it would have collapsed
in a synchronous messaging environment.
• Scalability and optimal use of resources : When process volumes increase,
MOM brokers employ dynamic routing and multiplexing techniques.
Dynamic routing allows clients and servers that are not prepro-
grammed to communicate as the MOM automatically connect the
requestor to the necessary service (without developer intervention).
In addition, in case of a server breakdown, the MOM platform can
dispatch a message to another backup server. Multiplexing is a func-
tion offered by MOM brokers that enables several applications to
share a message queue.
MOM has demonstrated an ability to deliver the benefits of asynchronous
messaging for applications and process-to-process interoperability, dis-
tributed transaction processing (such as banking, brokerage, airline reser-
vations), distributed enterprise workflow (such as process manufacturing,
insurance claims processing), real-time automation (such as utility and pro-
cess control), and systems management (such as distributed backup, soft-
ware distribution), among others.
5.5.1 Integration Brokers
Integration brokers perform necessary content and format transformation to
translate incoming messages into a format that the subscribing system(s) can
understand and utilize. Integration brokers are usually built on top of some
MOM implementations and so the general principles of MOM also apply to
them. An integration broker is usually built on a queue manager and routes
messages to applications. The integration broker allows multiple applications
to implement a published service with the broker providing application inte-
gration. In addition to these functions, integration brokers account for any
differences at the structural level of applications; integration brokers take
care of structural mismatches by keeping track of message schemas and by
changing accordingly the content of messages to the semantics of a specific
application. These unique capabilities of integration brokers enable them to
broker not only between applications but also between types of middleware.
An integration broker is an application-to-application middleware service
that is capable of one-to-many, many-to-one, and many-to-many message
distribution. An integration broker is a software hub that records and man-
ages the contracts between publishers and subscribers of messages. When a
business event takes place, the application will publish the message(s) corre-
sponding to that event. The broker reviews its lists of subscriptions and acti-
vates delivery to each subscriber for this type of message so that subscribers
receive only the data to which they subscribe.