[zeromq-dev] configuring zeromq pub/sub with epgm for low latency real-time messages

[Philip Miller]

Last week I posted this same question to stackoverflow. Since it has not been answered there, I thought I would try this mailing list. I have searched around a little and understand that unreliable udp unicast is not a supported protocol for zeromq. There is an open issue, UDP support #807, but no real activity on it. So my question is: how can I configure zeromq pub/sub using the epgm (or pgm) protocol to approximate conventional udp unicast performance (and behavior)?

The reason I am asking this question is twofold. First, in my realtime system I am publishing messages at a fairly high rate. If a message is not delivered, re-sending it is worse than dropping it and sending the next one. Second, there are many other use-cases within my system where the zeromq communication patterns apply. Plus, even for this scenario, there are use cases where a conventional zeromq tcp pub/sup is desirable. Using zeromq throughout my system makes a lot of sense, so I would like to use zeromq for this scenario as well without having to roll my own udp implementation. (I am a zeromq newbie and am not a network programming expert, so me adding udp to zeromq is out of scope.)

Since udp is not a current protocol in zeromq, how can I approximate the desired communication by setting the right options for epgm pub/sub?

I appreciate any feedback.

Thanks,
Phil

Links:
Stack overflow question: http://stackoverflow.com/questions/33390626/configuring-zeromq-pub-sub-with-epgm-for-low-latency-real-time-messages
Zeromq issue 807: https://github.com/zeromq/libzmq/issues/807#issuecomment-151758733