Brokers

A Broker is an entity that resides on a Broker Server. When a client connects to Broker Server, the client specifies the Broker with which it wants to interact.

Document types, which identify the kinds of documents that the Broker's clients can exchange.

Client Groups, which define specific properties and permissions that Broker applies to clients.

Client State Objects, which maintain information about the individual clients that use the Broker.

These objects are explained in more detail later in this chapter.

A Broker Server is installed with a single Broker, called "default." You can define additional Brokers on a Broker Server if necessary. For example, in the following scenarios, you will find it beneficial to configure multiple Brokers on the same Broker Server:

If you have a development environment in which you need to test different application environments, you might create multiple Brokers on a single Broker Server instead of installing and configuring separate Broker Server for each individual Broker environment that you need to emulate.

If you are using a Broker for publish-subscribe, and another Broker for JNDI, you can host both these Brokers on the same Broker Server. As both the publish-subscribe Broker and the JNDI Broker will be working together, hosting them on the same Broker Server makes it easy to manage the Broker Server instance.

When you configure multiple Brokers on a Broker Server, you can designate one of the Brokers to act as the default Broker . The default Broker is the one to which Broker Server will connect any client that does not explicitly specify the name of the Broker that it wants to use.

Following are the limitations when multiple Brokers are configured on the same Broker Server:

Only the Broker Server runs as an Operating System process. The Brokers are just logical entities that reside on the Broker Server. All Brokers hosted on the Broker Server share the system resources such as disk space, CPU, and memory.

If any of the Brokers require maintenance, all the other Brokers installed on the Broker Server are also affected.

If you are using multiple Broker Servers, maintaining these Broker Servers will cause overhead as you will have to use multiple storage directories and ports.

For information about creating, configuring, and managing Brokers, see Managing Brokers.