Categories
Programming

ZeromMQ REQuest/REPly pattern

More zeromq testing. See also PUB/SUB.

This pattern is for a reply&request situation where one machine asks for data from another machine. The pattern enforces an exchange of messages like this:

REQuester always first sends, then receives.

REPlyer always first receives, then sends.

Requester

The one-way delay here assumes we have machines with synchronized clocks. This might be true to within 1ms or so if both machines are close to the same NTP server.

The two-way delay should be more accurate, since we subtract two time-stamps that both come from the REQuesters system clock. Much better performance can probably be achieved by switching to C or C++.

Replyer:

Categories
Programming

ZeroMQ PUB/SUB pattern

I'm playing with zeromq for simple network communication/control. For a nice introduction with diagrams see Nicholas Piel's post "ZeroMQ an introduction"

Here is the PUBlish/SUBscribe patter, which usually consist of one Publisher and one or many Subscribers.

Publisher:

And here is the Subscriber: