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I have a setup like the one illustrated below. The router is a standard commercial home router and wireless AP, and computer B is a Raspberry Pi running Ubuntu, and it has one ethernet interface and one Wifi interface. B gets one IP from the router's DHCP server (on /24 subnet) over Wifi, and serves IPs from its own DHCP server (also /24 subnet) on the ethernet interface.

10.0.1.2       10.0.1.1
               10.0.0.2            10.0.0.1            10.0.0.3
 -----           -----            ----------            -----
 | A | ---ETH--- | B | ---WIFI--- | ROUTER | ---WIFI--- | C |
 -----           -----            ----------            -----

This setup is for running ROS2/DDS (A and B are internal in the robot and C is the control computer), but from what I understand I can't get messages from A to C since they're on different subnets (DDS uses UDP multicast).

  1. Is it possible to use B to bridge the Wifi subnet and the ethernet subnet? If not,
  2. How can I set up the routing table on B to correctly forward UDP multicast messages between the two networks?
eirik-ff
  • 101
  • Defining the network as `10.0/16` will make everything one network, if possible. – harrymc Aug 10 '23 at 11:33
  • @harrymc Will this correctly connect the two physical mediums though? E.g. will a packet sent from A be received at C correctly without any additional setup, or would I have to set up the routing table for this to work? Furthermore, the fact that DDS uses UDP multicast makes it more difficult and it's not obvious to me if the multicast packets will be forwarded through B correctly with a `10.0/16` network. Do you have any experience with this? – eirik-ff Aug 10 '23 at 12:22
  • That depends on the router and on B. Usually the arp requests pass over the entire physical network, so the computers can be found by their IP. – harrymc Aug 10 '23 at 12:54

0 Answers0