WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

10.4.1 Default messaging provider concepts
This section describes some concepts briefly in order to understand the basic
intent of the topologies.
Service Integration Bus
The Service Integration Bus (SIBus, or just the bus) provides a transport
mechanism for WebSphere Application Server default messaging provider. It is a
group of interconnected WebSphere Application Servers and a cluster of
WebSphere Application Servers that have been added as part of the bus. Each
member of the bus has a messaging engine so that the applications can connect
to the bus.
Message Engine
The Messenging Engine (ME) is a component of WebSphere Application Server.
It communicates messages to destinations, in cooperation with the other MEs of
other bus members.
Destinations
A destination is defined within a bus and represents a logical address to which
applications can attach as message producers, consumers, or both. There are
different types of destinations, which are used for different message models,
such as point-to-point or publish/subscribe. Destinations are associated with a
messaging engine using a message point.
Message point
A message point is the location on a messaging engine where messages are
held for a bus destination. A message point can be a queue point, a publication
point, or a mediation point (this is a specialized message point):
► Queue points
A queue point is the message point for a queue destination. When creating a
queue destination on a bus, an administrator specifies the bus member that
will hold the messages for the queue. This action automatically defines a
queue point for each messaging engine associated with the specified bus
member.
If the bus member is an application server, a single queue point will be
created and associated with the messaging engine on that application server.
All of the messages that are sent to the queue destination will be handled by
this messaging engine. In this configuration, message ordering is maintained
on the queue destination.
Chapter 10. Messaging 341