ØMQ/2.2 - The Guide

// Simple request-reply broker in Node.js

var zmq = require('zmq')
, frontend = zmq.socket('router')
, backend = zmq.socket('dealer');

frontend.bindSync('tcp://*:5559');
backend.bindSync('tcp://*:5560');

frontend.on('message', function() {
// Note that separate message parts come as function arguments.
var args = Array.apply(null, arguments);
// Pass array of strings/buffers to send multipart messages.
backend.send(args);
});

backend.on('message', function() {
var args = Array.apply(null, arguments);
frontend.send(args);
});