In my case, I'm forwarding videoroom stream to streaming plugin + ffmpeg (requires 8 udp ports per videoroom) which runs in the same instance of janus. I've full control on forwarders ports due to streaming plugin config + nodejs code. I can set same port range for my forwarder port generator code. But I've no control on videoroom ports, I don't now it's boundaries. Need to create more complex mechanism for choosing forwarder ports like decide first, check is in use, redecide if in use, check again and so on...