A component is a broker or a User Name Server.
A broker processes messages and a User Name Server extracts information from a security product and makes it available to brokers and the workbench.
The component name is the external name of the component and is used, for example, in the WebSphere Business Integration Message Broker workbench.
You only need a User Name Server if you are using Publish/Subscribe security. This User Name Server can exist anywhere in the network, including z/OS.
Each component has its own runtime environment in UNIX System Services and needs its own WebSphere MQ queue manager, although a broker and User Name Server can share a single queue manager. A broker component also needs access to a database.