WebSphere Event Broker Version 6.0 technical overview

WebSphere Event Broker enables information packaged as messages to flow between different business applications, ranging from large legacy systems through to unmanned devices such as sensors on pipelines.


Product overview

Message routing

Messages can be routed from sender to recipient based on the content of the message.

The message flows that you design control message routing. A message flow describes the operations to be performed on the incoming message, and the sequence in which they are carried out.

Each message flow consists of:

IBM supplies built-in nodes and samples for many common functions. If you require additional functions, you can deploy user-defined nodes that have been created and supplied by WebSphere Message Broker Version 6.0 users or by independent software vendors and other companies.

You create message flows in the Message Brokers Toolkit; an integrated development environment and broker domain administration console.

Create the run time

The work of routing messages takes place in a broker. Brokers contain a number of execution groups; processes in which message flows are run.

Brokers are grouped into broker domains. Each domain is coordinated by a Configuration Manager. There can be many brokers, and each can be running on a different system. This provides protection against failure, and can separate work across different divisions in a business.

The system administrator creates the Configuration Manager with a command line instruction. The Configuration Manager uses an internal repository to store information relating to its broker domain.

The system administrator similarly creates one or more brokers, linking each to a particular Configuration Manager, thus making them part of the domain controlled by that Configuration Manager. Each broker uses a database to store the information it needs to process messages at run time.

The Configuration Manager also displays the users and groups in the Access control lists that you use to set user permissions, see Publish/subscribe below.

Develop applications

After the system administrator has created and connected the components of the broker domain, an application developer creates and modifies message flows using the workbench.

Different perspectives in the workbench are used to develop message flows as well as to administer one or more broker domains.

A repository can be used to provide access control and version control. A repository also allows multiple developers to work on the same resources in parallel.

You can use WebSphere MQ for communication between application and brokers. Other communication protocols you can use are:

Deploy applications to the run time

When message flows have been created using the workbench, executable data can be deployed (transferred) to one or more brokers.

You can deploy data in one of two ways:
  • From the workbench
  • Using a shell command

When you deploy message flows, they are compiled and enveloped in a broker archive (bar) file, and sent to the Configuration Manager. The bar file has configurable system properties. You can override properties such as queue names, without the need to change source files or redevelop the message flow. This makes it easier to move definitions between systems.

The Configuration Manager opens the envelope, removes the contents, makes a record of the information that it has received, and routes the information to the appropriate brokers. (The envelope is discarded when the information it contains has been retrieved.) Each broker stores the information in its own local database. This means that, when a broker has sufficient information, it can continue processing messages even if it is no longer connected to its Configuration Manager.

The Configuration Manager coordinates all activity between the workbench and brokers within its domain. WebSphere MQ messaging is used between the workbench, the Configuration Manager, and the brokers.

Publish/subscribe

A publishing application sends a message about a named topic to a broker. The broker passes the published message to those applications that have registered an interest in that topic. The publisher and the subscriber are unaware of the other's existence.

The broker handles the distribution of messages between publishing applications and subscribing applications. Applications can publish on, or subscribe to, many topics as well as apply more sophisticated filtering mechanisms.

An optional User Name Server in the broker domain controls who is authorized to publish or subscribe to topics. You set up and administer topic-based security from the workbench.

You set user permissions at individual or group level using Access control lists.