[zeromq-dev] use zeromq for pgm audio broadcast to android devices ?

Pieter Hintjens ph at imatix.com
Wed Jan 2 20:40:54 CET 2013

I'm pretty sure (but Stephen can confirm) that WiFi switches do not
offer IGMP snooping, which PGM requires.

Over WiFi your choices are either TCP, for up to 8-10 devices, or UDP
multicast (probably with recovery over TCP) thereafter. I've not seen
an open source UDP+0MQ mass transfer protocol; it would be

You need to beware with any multicast over UDP since the bitrate the
switch will use will be extremely low, even if all devices are close

The quality of work you can do over WiFi depends seriously on the WiFi
switch quality, interference, and physical spread of the network.


On Wed, Jan 2, 2013 at 7:27 PM, Dan Reardon <dtr29 at hotmail.com> wrote:
> We are new to ZeroMQ and want to use it to distribute media over wifi to
> phones and other devices, potentially a very large number.
> (a) Has anyone used PGM over WIFI to devices yet? Anyone tried it with
> hundreds or thousands of phones? (b) How well does it (or should it) work?
> (c) If the wifi / electrical environment is dirty, will zeroMQ's queuing
> mechanisms get in my way? (e) What other issues should I expect to have to
> work around? (f) Tricks and tips?
> We do not need or want
> "guaranteed delivery", as this is a real time broadcast, missing
> audio segments should be substituted with silence when the cannot
> be obtained in time to keep up with the audio stream. Will we run into
> problems BECAUSE of message queuing we don’t want or is there a way to get
> in under that layer and avoid queues overflowing, etc.?
> Is there any chance that anyone would want to implement Uflood, Ucast or any
> other protocol specifically designed for wifi? How do we get this onto the
> “wish list” or product road map?
> We may be in a position to provide a testbed environment for large-scale
> wifi testing if someone else wants to develop the code! Who should we be
> talking to? Anyone interested in being the lead archtect or developer if we
> can support testing?
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