[zeromq-dev] Fwd: Exact matching on subscription topics

[Staffan Gimåker]

On Tue, 2012-01-10 at 13:51 +0100, Martin Sustrik wrote:
> > Looked the e-mail outlining the proposed wire format; it looks
> > good. That's essentially equivalent to what I did in my quick-n-dirty
> > prototype, only with larger cmd-id and algo-id fields. Is there a
> > specific reason to use 16-bits for the cmd-id? Seems like one byte would
> > more than suffice, wasting a byte is not a big deal though.
> 
> The only reason being is alignment of payload to 32-bits as all good 
> network protocols do :)

Gotcha.

> Nope. What can be done is that if the code is not aware of particular 
> matching algorithm, it transparently passes the subscription upstream. 
> Also it marks the downstream node that it've got the subscription from 
> as subscribed for *all* messages.
> 
> This allows old devices to work with new matching algorithms, although 
> in a less efficient way.

Ok, makes sense. So the intermediary device would still have to store
all the subscriptions it received and resend them if the upstream pipe
is disconnected, right?

/S