[ros-users] re-subscription

[Klaus Petersen]

Brian Gerkey さんは書きました:
> On Thu, Mar 4, 2010 at 3:51 AM, Klaus Petersen
> <klaus at takanishi.mech.waseda.ac.jp> wrote:
>> I have a very basic problem: First, I establish a connection between a
>> publisher node and a subscriber node. At this point I can receive
>> messages from the publisher with the subscriber node. But when I
>> re-start my publisher node (quit and run again) the subscriber does not
>> automatically resubscribe to the message. I have to restart the
>> subscriber as well to be able to receive again. Is this the normal
>> behavior with ros or am I doing something wrong? I have quite a big
>> robot control program tied to one of the nodes, so restarting along the
>> way (the initialization of the robot takes ages) is very troublesome.
> 
> hi Klaus,
> 
> Something's going wrong there.  When your publisher is restarted, it
> should re-advertise with the master, which should send the new
> publisher list to your subscriber, which should then re-connect to
> your publisher.
> 
> You can test this behavior with roscpp_tutorials/talker and
> roscpp_tutorials/listener; no matter in what order they're
> (re)started, listener will always connect to talker.
> 
> Can you tell us something about your publisher and subscriber? Is
> there anything unusual about your subscriber?
> 
> 	brian.
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Hi Brian,

The problem is consistent for the tutorials nodes. I think there is 
someting wrong with the communication of my nodes with the master. My 
system is running on one linux, one macos and one windows box. I had 
trouble running roscore on the linux computer for some reason. After 
running it on the mac everything seemed to be ok until I encountered the 
reported problem. I think it comes down to some trouble with my linux 
box. I did the connectivity checks from ros.org, which showed some 
problems with name resolution in my network. I fixed that by setting 
ros_ip. Still it seems like some ports on my ubuntu box let go data in, 
but no data go out. Is there any common mistake that leads to that 
symptom? Anyway, I guess general network trouble is out of the scope of 
this mailing list :)

Klaus