[zeromq-dev] ZRE/Zbeacon improvement proposal

[Pieter Hintjens]

On Sat, Oct 26, 2013 at 11:54 PM, Arnaud Loonstra <arnaud at sphaero.org> wrote:


> Well, multicast is designed for it. So if multicast is an option next to
> broadcast you would get it for free. :) Just set the TTL to 1 by default
> if you want to be safe. Of course having a zeromq router to handle it
> could be an option.

Sounds good. TTL default to 1, yes.

> Agreed, state propagation is of course not essential. But wouldn't you
> agree broadcasting on exit would be better than determining a nodes
> state by trying to connect to it?

Yes, it's a natural pattern to say "bye bye" when leaving a room or
ending a phone call, precisely to save the other person from wasting
time wondering what happened. And the fallback is already there. So
for leaving, it makes sense to broadcast a "bye bye" beacon. I was
confused because you proposed five states to signal one thing, which
seemed a lot.

Given this use case, I'd modify the existing protocol in a compatible
way. Right now we broadcast the port number to signal availability. it
would be natural to broadcast a port number zero to signal
unavailability.

That's a safe change, minimal, and does what you need. Along with
multicast as an option, and we make nice progress.

-Pieter