[zeromq-dev] Asymmetrical PUB-SUB problem

[Mark Sutheran]

I'm having a strange asymmetrical problem with tcp PUB/SUB between two boxes - it appears to fail one way.



Details: 
* zeromq version: 3.2, using the Java wrapper.
* Scenario has two machines A (Ubuntu, x64) and B (Angstrom, arm8)
* Both connected directly via wireless interface (B is acting as AP).

Scenario 1: A->B. All as expected.
* Box A:PUB bind wlan0 - publish messages 1x per second.
* Box A:SUB connect <ipx> - see messages, yay!
* Box B:SUB connect <ipx> - see messages, yay!

Scenario 2: B->A. Problem
* Box B:PUB bind wlan0 - publish messages 1x per second.
* Box B:SUB connect <ipy> - see messages, yay!
* Box A:SUB connect <ipx> - no messages, boo!

However, if I change pattern...

Scenario 3: Comparison
* Box A: REQ - make n requests.
* Box B: REP - send n replies. Replies received on Machine A as expected. Yay.

There are absolutely no messages received at the SUB on A from the PUB on B (irrespective of the process start order) however, connecting a SUB on B to the interface's ip works fine. If I reverse the boxes I see the behaviour I expect - i.e. the SUBs on both boxes see the messages. As a contrast: if I run a REQ on A and REP on B, everything works as expected and the message sent from B is received at A.

This is presumably a problem with my hardware/OS but I'm not sure even where to start looking... any pointers would be greatly appreciated.

Cheers,
Mark
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.zeromq.org/pipermail/zeromq-dev/attachments/20120707/aab2fab0/attachment.htm>