[zeromq-dev] is pgm transport working in alpha3?

Martin Sustrik sustrik at 250bpm.com
Fri Nov 6 22:18:00 CET 2009

Hi Yuri,

>So, last question on this. Can I use zmq_forwarder to bridge between:
>1. TCP and Multicast
>2. Multicast and Multicast (different services of course)

The answer is yes for both questions. The former scenario makes sense
when distributing messages received from WAN (TCP) on a LAN (PGM). The
latter one can make sense on a router to redistribute incoming multicast
traffic on a LAN.

>In general, zmq_forwarder could be a very interesting element in this
>solution. By looking at the code, it seems it can open multiple input
>channels and multiple output channels.

That's right.

>Is it intended to be a simple fan-out solution? Any plans on supporting
>routing/filtering rules here?

So far it's simple fanout. What goes in, goes out. In the future it
should gather subscriptions/unsubscriptions from the downstream
components and push them upstream to eliminate excessive network traffic.

>Also, for an RPC style messaging, I wound need to run 2 of forwarders: one
>for A->B, and another for B->A. Is this the idea? It would be better to have
>one forwarder process do both.

For RPC style messaging req/rep sockets should be used rather than
pub/sub ones. Also, there should be a different device there, not a
forwarder, but a shared queue. Unfortunately, it's not implemented yet.


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