def _get_interface_name_from_hosting_port(self, port):
try:<EOL><INDENT>vlan = port['<STR_LIT>']['<STR_LIT>']<EOL>int_prefix = port['<STR_LIT>']['<STR_LIT>']<EOL>return '<STR_LIT>' % (int_prefix, vlan)<EOL><DEDENT>except KeyError as e:<EOL><INDENT>params = {'<STR_LIT:key>': e}<EOL>raise cfg_exc.DriverExpectedKeyNotSetException(**params)<EOL><DEDENT>
Extract the underlying subinterface name for a port
e.g. Port-channel10.200 or GigabitEthernet0/0/0.500