Enterprise Application Integration (EAI) - Guide to Cloud Computing for Business and Technology Managers - page 99

There are three popular types of asynchronous communications:
a. Message passing—This is used in situations where information
needs to be transmitted but a reply is not required. This needs a
reliable network for guaranteed delivery.
b. Publish/subscribe—This is used in situations where a reply is not
required, but unlike all other cases, the recipient is determined
based on the content of the request and the predeclared interest
of the receiver application. This type of communication is use-
ful for STP type of functional integration (see Section 4.2.2.2.3,
“Straight-Through Processing”).
c. Broadcast—This is used in situations where again a reply is not
needed but the request is sent to all the applications and each
receiver decides if it is interested in the request/message and
accordingly processes that request/message in accordance with
the business and functional logic programmed into each of the
receiver systems.
4.2.1.3 Middleware Options
Middleware is software that enables disparate applications to interact with
each other—it facilitates the communication of requests between software
components through the use of predefined interfaces or messages. The five
basic types of middleware are as follows:
1. Remote procedure call (RPC)—This is based on the notion of devel-
oping distributed applications that integrate at the procedure level
but across a network
2. Database access middleware—This is based on the notion of devel-
oping distributed applications that integrate at the distributed data
level whether in files or databases but across the network
3. Message Oriented Middleware (MOM)—This is based on the notion
of developing distributed applications that integrate at the message
level but across the network
4. Distributed object technology (DOT)—This is based on the notion
of developing distributed applications that integrate at the interface
level but those that make the application look like an object
5. Transaction processing monitor (TPM)—This is based on the notion
of developing distributed applications that integrate at the distrib-
uted transaction level but across the network
4.2.2 Models of Integration
An integration model defines the approach and configurations used to inte-
grate software applications depending on the nature and methods of the