In order to run the installation system a working network setup and ssh session is needed on S/390.
The booting process starts with a network setup that prompts you for several network parameters. If the setup is successful, you will login to the system by starting a ssh session which will launch the standard installation system.
On S/390 you can append boot parameters in the parm file. This file can either be in ASCII or EBCDIC format. Please read Device Drivers and Installation Commands for more information about S/390-specific boot parameters.