Multicast in docker

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Original report (archived issue) by Vinayak Jagtap (Bitbucket: vinayak_jagtap).

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The multimaster options in ROS need multicast to be enabled on the system otherwise the connection breaks every few minutes. Is that possible in Docker? Has anyone successfully configured multimaster that is running for something like 30minutes or more?

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Original comment by Vinayak Jagtap (Bitbucket: vinayak_jagtap).

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• set component to "cloud"

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Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

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Can you offer some insight as to why you need multimaster? Normally, multimaster is used when there are multiple robots.

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Original comment by Ian Chen (Bitbucket: Ian Chen, GitHub: iche033).

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@nkoenig, I think multi-master is being used to relay data from Sim to OCU through FC. This is mainly because ROS_MASTER_URI is set in the simulator instance and the simulator <-> OCU communication is blocked.

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Original comment by Vinayak Jagtap (Bitbucket: vinayak_jagtap).

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That's right, we are using multimaster for forwarding data on topics to OCU.

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Original comment by Akihiko Honda (Bitbucket: akiHonda).

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Our team are also planning to use multimaster method. We work hard to realize it and got some advance, however it is not completed. I think the problem is a location of ROS master and communication blocking.

Is there any chance to get new option to choose the location of ROS master ? (If we predict the real mars mission, ROS master will be located in FC, not mars environment.)

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Original comment by Rud Merriam (Bitbucket: rmerriam).

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I had some luck locally using the NMap ncat to do a bidirectional transfer of ROS topics. That was local docker to my desktop. I stumbled on getting it to work with CouldSim.