Communication ports in PX4 SITL simulation using ROS and Gazebo

Hello Guys,
I hope you are safe and doing well,
I have set up PX4 SITL firmware on my Ubuntu 18.04 and ROS Melodic-based system.
I was skimming through the launch files (single_vehicle_spawn.launch) and did not understand the meaning of some parameters/arguments like mavlink_udp_port , mavlink_tcp_port , gst_udp_port , video_uri , mavlink_cam_udp_port , mavlink_id .
I get that they are communication ports MAVROS uses to connect Gazebo simulation and ROS but I would like to know about each of them in detail.

Any help and resources are appreciated,