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fkie multimaster connection issues - firewall? [closed]

asked 2015-12-14 17:04:42 -0600

chrisb gravatar image

Hello,

I have 3 hosts with a roscore each. Two of them are Ubuntu ARM and one is the normal desktop version of Ubuntu.

Starting the fkie multimaster discovery and sync does work perfect between the Ubuntu ARM hosts but the Desktop does not recognize either one. http://wiki.ros.org/multimaster_fkie

I'm wondering if my desktop might have a default firewall rule that prevents a proper broad cast between the master discovery instances. The three hosts can connect if I run roscore on one machine and set the others up for that particular one. I'm not sure which connections the discovery node uses (broadcast and so on) that's why I think there might be a firewall issue.

I hope somebody can help me with that.

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Closed for the following reason question is not relevant or outdated by tfoote
close date 2017-04-20 13:46:44.040282

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I remembered doing something similar to your case for multimaster system. I used 3pcs. I used this paper. Have you tried it?

Vinh K gravatar image Vinh K  ( 2015-12-15 02:34:50 -0600 )edit

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answered 2015-12-16 14:34:51 -0600

chrisb gravatar image

Hello Vinh,

I did use the tutorial on the ROS page but the paper gives me a lot more information. Thanks for the info.

rosrun master_discovery_fkie master_discovery _mcast_group:=224.0.0.1

specifying the multicast address helped a little and my third host is visible to all others now. The syncronizer how ever gives me an error while publishing a test message:

Error while decode message: newer heartbeat version 3 (own: 2 ) detected, please update your master_discovery

Cause of that, it is not synchronizing the topics from this node. The master discovery is the latest version though.

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Hi chris try to not put that as an answer yet. By synchronizer did you mean the

rosrun master_sync_fkie master_sync

that is giving you errors?

Vinh K gravatar image Vinh K  ( 2015-12-16 23:05:17 -0600 )edit

Yes I think so. The error occurs while publishing the first topic.

chrisb gravatar image chrisb  ( 2015-12-17 00:15:04 -0600 )edit

i see. I'm not sure where the issue is. If this is something that is very urgent, I would keep updating this question so that way it will always be on the latest list of question ask.

Vinh K gravatar image Vinh K  ( 2015-12-18 20:53:18 -0600 )edit

I heard that many people say single master is much easier rather than multi-master. I am working on that right now for my 3 turtlebots. Soon it will be 6. Is single master an option for you to try at this point, Chris?

Vinh K gravatar image Vinh K  ( 2015-12-18 20:55:15 -0600 )edit

Thanks Vinh,

I could run my system as a single master in the lab. I did this for the developing phase. The issue is much more the in field usage where the network connection is not as good. I don't want any nodes crashing during network outage. And also a reconnection if the network comes back.

chrisb gravatar image chrisb  ( 2015-12-29 13:19:43 -0600 )edit

so did you get it to work Chris?

Vinh K gravatar image Vinh K  ( 2016-01-15 12:03:55 -0600 )edit

unfortunately not. It works fine on my two embedded platforms but not on my desktop.

chrisb gravatar image chrisb  ( 2016-01-28 11:35:44 -0600 )edit

It looks like this problem is not solved. Vinh: Did you figure out if this is firewall or processor architecture related?

chrisb gravatar image chrisb  ( 2016-09-20 12:32:25 -0600 )edit

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Asked: 2015-12-14 17:04:42 -0600

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Last updated: Dec 16 '15