The thing I most dislike about 0MQ is the overly conceptualized socket typing (ZMQ_DEALER etc), and the way the documentation tries to cram all the combinations in to idiomatic 'patterns'.

All I want to be able to express when I send() is:

  1. Whether it's a Broadcast, Unicast or Anycast message
  2. Whether I'm sending globally, or targeting a 
     subset of peers (subscribers to some filter).

Forgive me if these mappings are flaky, it's been a while since I used 0MQ.

  Target        Method       ~0MQ socket type

  Global        broadcast   -> ZMQ_PUSH
  Global        unicast     -> ZMQ_PAIR
  Global        anycast     -> ZMQ_DEALER
  
  Subscribers   broadcast   -> ZMQ_PUB/SUB
  Subscribers   unicast     -> ZMQ_REQ/REP
  Subscribers   anycast     -> ZMQ_ROUTER