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Next message pankaj Bhardwaj  posted on Thursday, October 16, 2008 - 12:28 pm
Hi,

Is it possible to have two way communication through DDS.

I want to send and receiver message two n nodes,can we do this through DDS.
Next message Niels Kortstee  posted on Thursday, October 16, 2008 - 01:27 pm
Hi,

Unfortunately I am having trouble understanding your question, but maybe the following provides an answer for you.

DDS provides an information-centric connectionless paradigm. This means communication takes place based on 'matching' information and not by addressing the physical location of a receiver by a sender (as it would in a connection-oriented environment).

Information is represented in DDS in the form of so-called Topics that are identified by a name, a type definition and a set of quality of service policies. Communication in DDS takes place between so-called Publishers and Subscribers. The matching between Publishers and Subscribers is transparently realized by the middleware itself based on Topics and independent of the physical location of these entities. To establish communication between a Publisher and a Subscriber, one only needs to create a DataWriter (sending) and a DataReader (receiving) for the same Topic (and make sure that their offered and requested quality of service policies match with each other).

This means that one can create any number of DataWriter and DataReader entities for one specific Topic independent of their physical location and they will communicate automatically (n-to-m).

If this does not answer your question, could you elaborate a bit more on it?

Best regards, Niels
Next message pankaj Bhardwaj  posted on Thursday, October 16, 2008 - 07:07 pm
Hi Niels, Thanks for replying.

Practically I want to send and recieve messages between two (or more) Linux box. I have installed DDS on both box.Both the box are on the same network and are connected through LAN.

Suppose the box are box A and box B.
I have started the InfoRepo on both the boxes, now I want to send message from box A to box B and also from Box B to Box A.

I want to know it it possible through DDS.

1)Kindly tell me if possible, how we can configure this setting.

I think we have to run both publisger and subscriber on both the boxes.
when publisher on box "A" publish the message it can be taken by subscriber of box "B"(both registerd for same topic.)

and when publisher on box "B" publish the message it can be taken by subscriber on box "A".

please correct me if I am wrong.
Next message Niels Kortstee  posted on Thursday, October 16, 2008 - 07:21 pm
Yes, that's correct. Additionally, the published messages will also be received by your subscriber on the same box.

For instance; your message published on box "A" will also be received by your subscriber on box "A".
Next message pankaj Bhardwaj  posted on Friday, October 17, 2008 - 05:31 am
hi Niels,

Thanks.

Publisher and subscriber on box "A" will be connected to InfoRepo of Box "A".

Publisher and subscriber of Box "B" will be connected to InfoRepo of box B.

ALl the communication will happen through InfoRepo.(Communication bus)

please tell me how the infoRepo on the box "A" and box "B" will be connected to each other, to make the global data space.
please tell me the file name where I have to make changes.
Next message Niels Kortstee  posted on Friday, October 17, 2008 - 01:01 pm
Hi Pankaj,

I don't know which DDS implementation you are using, but it sounds strange that you need to adapt a file to achieve communication between a specific Publisher and Subscriber, since it requires you to know the physical location of all participating entities on beforehand while the complete decoupling between publishers and subscribers is one of the most powerful features of DDS.
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