SaltStack uses ZeroMQ to communicate with SaltStack on other machines. https://github.com/saltstack/raet says SaltStack faced performance issues on massive deployments because ZeroMQ doesn't have a UDP transport and doesn't allow programmers to tune queues independent of transport. In other words, it was lack of UDP and of programmable queue. Or, was it really a problem of UDP and programmable queue? If so, I can think of solutions. Both ZeroMQ and nanomsg is capable of assimilating UDP transport though nanomsg makes it easier to do so by providing internal APIs for transport and messaging patterns. However, ZeroMQ and nanomsg don't seem to provide programmable queues. How could nanomsg satisfy SaltStack's messaging needs?