ZeroMQ-Publish/Subscribe

Publish/Subscribe is another classic pattern where senders of messages, called publishers, do not program the messages to be sent directly to specific receivers, called subscribers. Messages are published without the knowledge of what or if any subscriber of that knowledge exists.

Scenario #2 is more known, general pattern where multiple subscribers subscribes to messages/topics being published by a publisher. It is scenario #1 which is more interesting. Just like ZMQ.REQ which can connect to multiple ZMQ.REP, ZMQ.SUB can connect to multiple ZMQ.PUB (publishers). No single publisher overwhelms the subscriber. The messages from both publishers are interleaved.