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Issue with communication between Publisher/Subscriber FBs. [message #1778016]

Fri, 08 December 2017 01:52

Awais Tanveer

Messages: 21
Registered: April 2016

Junior Member

Hello,

I am trying to run through a simple publisher/subscriber example. I have deployed two instances of FORTE on a single but remote raspberry pi. Publisher and subscriber IDs are the same i.e. a multicast address and a port. Although FBs deployed on both FORTE instances run fine but they do not seem to be communicating. I have check that multicast is enabled on the ethernet interface. I have also checked through tcpdump that no multicast packets get transferred when I trigger REQ. The result of which no data gets transferred between publisher and subscriber. Attached is the configuration of my simple application deployed on separate FORTE instances on the remote raspberry pi.

Am I missing something? Any help would be appreciated.

Attachment: pubsub.png
(Size: 85.35KB, Downloaded 68 times)

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Re: Issue with communication between Publisher/Subscriber FBs. [message #1778024 is a reply to message #1778016]

Fri, 08 December 2017 09:46

Ben Schneider

Messages: 24
Registered: February 2017

Junior Member

Hi,

you could try to configure an explicit route for UDP multicast messages like follows:

route add -net 224.0.0.0 netmask 240.0.0.0 dev eth0

Cheers,
Ben

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Re: Issue with communication between Publisher/Subscriber FBs. [message #1778027 is a reply to message #1778024]

Fri, 08 December 2017 10:15

Alois Zoitl

Messages: 645
Registered: January 2014

Senior Member

Hi, it also looks that you are not correctly initializing your fbs. Especially the Subscriber has not got any initialization event. Maybe that is the issue. On the Publisher side I don't see where the init event is coming from. But it is in general not a good idea to do it in the same way as the REQ. The better setup is to do initialization separate to the control flow.

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Re: Issue with communication between Publisher/Subscriber FBs. [message #1778063 is a reply to message #1778016]

Fri, 08 December 2017 19:46

Martin Melik-Merkumians

Messages: 48
Registered: March 2016

Member

I had a similar issue on raspberry pi, although not with forte, but with multicast communication. Check if you have a default gateway configured, as at least in my case Raspbian was not able to send multicast messages without it.

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Re: Issue with communication between Publisher/Subscriber FBs. [message #1778118 is a reply to message #1778063]

Sun, 10 December 2017 22:34

Awais Tanveer

Messages: 21
Registered: April 2016

Junior Member

Thanks for the help. I will get back here after I try the solutions suggested.

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Re: Issue with communication between Publisher/Subscriber FBs. [message #1778205 is a reply to message #1778118]

Mon, 11 December 2017 22:08

Awais Tanveer

Messages: 21
Registered: April 2016

Junior Member

I have been able to make my solution work after adding a route in raspberry pi and also initializing pub and sub separately as advised by Alois. Thanks a lot for the help.

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