[zeromq-dev] ZMQ UDP Support
sustrik at 250bpm.com
Sat Apr 10 07:24:51 CEST 2010
> I notice no direct support for UDP. From snippets I read here and there
> it seems that UDP usage is via PGM. Few quick questions –
There's a "epgm" (encapsulated PGM) transport. What it means is that
standard PGM packets are wrapped in UDP packets. Thus it's still
reliable multicast rather than unreliable unicast/multicast as you would
expect with UDP.
Several people have hinted that they would like to write a real UDP
transport for 0MQ but nobody have yet contributed anything.
> * Is there a difference in terms of performance or capability in this case?
EPGM should be more or less equal w.r.t. performance to PGM.
> * What if one wants to implement a unicast delivery over UDP? Can it be
> done using PGM?
In theory, you can set PGM retransmit window so small that no repair
That way you would actually mimic unreliable transport using a reliable
one. The better idea (in terms of performance) would be to write real
UDP transport for 0MQ. Not a big deal but someone has to do it :)
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