def setTxMode(self, vportList='all', txMode='interleaved', timeout=70):
        """
        Description
           set TxMode of the vports

        Parameter
           vportList: <list>: vports to set the transmitMode on.  Default = all
           txMode:    <str>: transmit mode setting -  can be either 'interleaved' or 'sequential'
           timeout:   <int>: the timeout value to declare as failed. Default=70 seconds.
        """
        if vportList == 'all':
            response = self.ixnObj.get(self.ixnObj.sessionUrl+'/vport')
            vportList = ['%s' % vport['links'][0]['href'] for vport in response.json()]

        # vportList: ['/api/v1/sessions/1/ixnetwork/vport/1', '/api/v1/sessions/1/ixnetwork/vport/2']
        for eachVport in vportList:
            self.ixnObj.patch(self.ixnObj.httpHeader+eachVport, data={'txMode':txMode})