FM or method for validation of network path

how to validate file path which is on the network, weather given file exists in the given path or not.

kindly suggest Function modules or any method.

method FILE_EXIST in the class CL_GUI_FRONTEND_SERVICES is taken care only for the local path which is there in the local system. I need it for the network path.

After that, i would like to read excel file from the network.

Kindly suggest any method.

i am using F4 function module to take input to the file name parameter. if user didn't used those options and directly entered the file path then i have to validate that path.