Publish and Subscribe Distribution	The message broker sends a message to subscribers that want to receive it. This divides into topic-based and content-based
Topic-based publish and subscribe	Distributes messages depending on their subject line; this subdivides into broadcast and list based.
Broadcast-based publish and subscribe	A topic-based distribution. An event publisher creates a message and broadcasts it to the local area network. Each listening node has a service node that inspects the subject line. If the subject line matches a subject the node subscribes to, then the node processes the message. Else, the listening node ignores the message.
List-based publish and subscribe	A topic-based distribution. You identify a subject and maintain a list of subscribers for that subject. When an event occurs, the subject notifies each subscriber on the subscription list.
Content-based publish and subscribe	Distributes messages depending on the content of the message. Each combination of information items can be seen as a single dynamic logical channel. (This exponential enlargement of potential logical channels has changed the way to implement a pub/sub system.)
Publish and subscribe middleware	Publish and subscribe distribution is possible via any kind of component communication technology, but is most usually associated with a mediator or message broker.