This can be either a network problem or a matching problem (incompatible QoS, different topic names...).
For network issues, you check that the remote machine is accessible from your computer? You can do it by running "ping <IP>".
If there are no communication issues, be sure that both endings are in the same domain and using the same topic names. Also, the configuration is the same, especially if using Advance create DataReader/DataWriter. Double-check that force array mapping options are the same in both machines.
If all configuration is ok. Check if there is a match issue by opening Admin Console, join to the domain you are using, and seeing if the remote machine appears. In case it does you can see if the DataReaders and DataWriters match by clicking on the match analysis button. In case it a matching issue there you will find the reason. For basic concepts of Admin Console you can see the documentation available from the 'Help' menu in the application.
Thanks. We used the examples and the QoS are the same by default. We tried to ping each other and all timed out. So, you are right, it's the network problem.
I'm not a network guy and definitely need some education on that. My partner and I use different service provider, i.e. Bell and Rogers in Canada. Any direction as how I could move for the next step?
My goal for this project is, using DDS to communicate across network, so my students could control my Lego Robotics from their homes.
So, if I'm reading correctly, we can't just ping each other ip, but possibly ping a specific port? https://community.rti.com/howto/configure-rti-connext-dds-not-use-multicast,
Does that mean we need to specify the port to be open when using DDS? If so, how to do that? Should we set it in the NDDS_DISCOVERY_PEERS? https://community.rti.com/rti-doc/510/ndds.5.1.0/doc/html/tcp_transport/group__NDDS__TransportTCPPee...
NDDS_DISCOVERY_PEERS won't work for peers in different networks. You can use a VPN to connect with all your remote peers. This way all the remote peers are in the same network and will discover between them by multicast. So you wouldn't need to set up NDDS_DISCOVERY_PEERS.
Thanks for the VPN method. It's very strange I'm still not able to make it working. My partner and I installed a VPN (ProtonVPN) and point to the same server IP (confirmed). As for the Read/Write program, we are using the default example "RTI Connext DDS Read String.vi" and the "RTI Connext DDS Write String.vi". The Domain id are same "0", and the Topics are the same as well "Hello LV String". Very strange, he just couldn't see my written messages...
I also removed the NDDS_DISCOVERY_PEERS...
Can you check that the VPN is working fine? You can ping to the remote peer by doing "ping <IP of your partner>" and see if the remote replies.
Keep in mind that the IP of your partner is not the same as you used before. You have to use the IP of the VPN network interface of your partner. To list all the network interfaces with IPs type "ipconfig" on your partner's computer. Probably you'll see one with the name "ProtonVPN" or something similar. That is the one you should ping.