[zeromq-dev] Multicast and wlan0

[Will Heger]

So I've just started working with (er attempting) epgm and I haven't been
able to read a single message yet.  Other patterns like request-reply have
worked fine.  The pyzmq test code (stolen from
http://code.saghul.net/implementing-a-pubsub-based-application-with) is
listed below and below that is my ifconfig.  I'm on ZMQ 2.2 with-pgm
compiled.

So my questions are as follows:

1. should the code below, 'just work' (tm) as in pick a 239.192 address and
go?

2. My aim is to use epgm for LAN network discovery among different wireless
devices.  The LANs I will deploy on will be pretty generic home networks.
 I write this because I'm unclear if that's even a reliable strategy or if
there is some additional network provisioning that might need to be
performed.  I'll do UDP broadcast and/or scanning if it comes to it, but
this seemed smarter.

3. Finally, a side question (I believe).  I've tried to use "wlan0" to
explicitly declare what network interface I want to use (as in tcp://wlan0;
192.168.1.1:5000) and that never works, although omitting the interface
works fine for request-reply.


# producer

import zmq

context = zmq.Context()
socket = context.socket(zmq.PUB)
socket.setsockopt(zmq.LINGER, 0)    # discard unsent messages on close
socket.connect('epgm://239.192.1.1:5000')

while True:
    msg = raw_input('> ')
    if msg == 'quit':
        break
    else:
        socket.send(msg)
socket.close()


# consumer

import zmq

context = zmq.Context()
socket = context.socket(zmq.SUB)
socket.connect('epgm://239.192.1.1:5000')
socket.setsockopt(zmq.SUBSCRIBE, 'test')
socket.setsockopt(zmq.SUBSCRIBE, 'topic_1')

while True:
    data = socket.recv()
    print data

---------------

eth0      Link encap:Ethernet  HWaddr XX:XX:XX:XX:XX:XX
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:18

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:187 errors:0 dropped:0 overruns:0 frame:0
          TX packets:187 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:24696 (24.1 KiB)  TX bytes:24696 (24.1 KiB)

wlan0     Link encap:Ethernet  HWaddr XX:XX:XX:XX:XX:XX
          inet addr:192.168.2.100  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: XXXX::XXXX:XXXX:XXXX:XXX/XX Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:139760 errors:0 dropped:0 overruns:0 frame:0
          TX packets:101421 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:163638433 (156.0 MiB)  TX bytes:15775138 (15.0 MiB)
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