ROS_MASTER_URI and ROS_HOSTNAME for Connecting to a robot [closed]

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Hello Community,

I am facing a problem while connecting to a real robot and i am not sure how to set it this up. I am trying to connect with a universal robot ur10e with a nvidia jetson nano running Ubuntu 20.04 and ROS noetic on it. As i am trying to test reinforcement learning algorithm.

I ma trying to follow steps mentioned on the bottom of this page's link (https://github.com/jr-robotics/robo-g...) as i am trying to implement this repository but somehow i am confused and i think i am making some mistake.

These are the steps mention on the repo

Real Robot Server

Connect to the robot's network

In a terminal window start the ROS driver:

Set ROS Master IP: export ROS_MASTER_URI=http://192.168.12.20:11311

Check the IP of the PC on which the UR ROS Driver will be running with ifconfig

Set the PC IP export ROS_IP=192.168.12.195 (replace with IP of the PC)
Launch the driver roslaunch ur_robot_driver ur10_bringup.launch robot_ip:=192.168.12.70 (replace with IP of the robot)

In another terminal window start the Robot Server

Set ROS Master Ip: export ROS_MASTER_URI=http://192.168.12.20:11311
Launch UR 10 Robot Server roslaunch ur_robot_server ur10_real_robot_server.launch gui:=true max_torque_scale_factor:=0.5 max_velocity_scale_factor:=0.5 speed_scaling:=0.5

To let you know i am connected with a universal robot ur10e with ethernet cable and i have set my robot's IP : 192.168.12.70 and my ubuntu machine on IPV4 : 192.168.12.195

When i try to follow steps and i looked at internet and some comment suggested to start roscore in another shell, but after starting roscore i get this error

  error:Unable to contact my own server at [http://192.168.12.20:42059/].This usually means that the network is not configured properly.

I would be glad if someone can tell me what will be my network configuration.

Thanks in Advance