Now, we know how to communicate between nodes in different machines that are in the same network. But what if the nodes in different machines have the same topic names? Consider the example shown in the following diagram:

In a mobile robot, a move_base node would need sensor and map information to give out trajectory points as cmd_vel commands. If you're planning to use another mobile robot in your application, the mobile robots may have the same topics for communication since both are in the same network and, as a result, this would cause chaos. Both robots may try to follow the same commands and do the same operation instead of performing tasks individually. This is one of the major issues of using a common ROS network. There is no way the robot understands individual controls as they have the same topic name in the network. We'll learn how to overcome this scenario in the upcoming section.