[zeromq-dev] Publisher side filtering

[Martin Sustrik]

Hi Chris,

> Will subscription forwarding be optional?  Or controllable to a certain point
> within the chain?  eg. a socket option that says don't forward subscriptions.
> Or perhaps better yet, a socket option that says do forward subscriptions (as
> that way uni-directional transports still work by default, as I'm assuming they
> no longer will otherwise?).
>
> Back to the point, sometimes publishers are fairly poor folk, simply sending to
> a central broker who is much more capable at handling many connections and doing
> filtering.

You can handle the load of connections using central server irrespective 
whether subscription forwarding is used or not.

The only difference is that with subscription forwarding the server 
informs the publisher about what messages it wants, thus the publisher 
can drop the messages that the server is not interested in straight away.

That could be particularly useful for publishers on poor hardware as 
they can drop some of the messages instead of pushing them all to the 
network.

Martin