We have to use "sth::load_xml" command.
Purpose: Loads test configurations from a previously saved XML file, and returns a Spirent TestCenter project handle.
Synopsis: sth::load_xml [-filename]
Argument: -filename Specifies the path of the XML file. This argument is mandatory.
Return Values: The function returns a keyed list using the following keys (with corresponding data):
handle Spirent TestCenter project handle
status Success (1) or failure (0) of the operation
log An error message (if the operation failed)