def startStopProtocolOnPort(self, protocol, portName, action='start'):
        """
        Description
            Start and stop a protocol on a specified port

        Parameters
            protocol: <str>: Protocol to start
            portName: <str>: Name of the port, eg: '1/1/11'
            action: <str>: start or stop a protocol, default is start

        Syntax
            POST: /api/v1/sessions/{id}/ixnetwork/vport/protocols/<protocol>
            DATA: {'args': 'api/v1/sessions/1/ixnetwork/vport/1'}

        Examples
            startStopProtocolOnPort(protocol='ospf', portName='1/1/11')
            startStopProtocolOnPort(protocol='ospf', portName='1/1/11', action='stop')

        """
        vport = self.portMgmtObj.getVportObjectByName(portName)
        if vport == None:
            raise IxNetRestApiException('PortName {0} not connected to chassis'.format(portName))

        url = self.ixnObj.sessionUrl + '/vport/protocols/' + protocol + '/operations/' + action
        vport = vport + '/protocols/' + protocol
        response = self.ixnObj.post(url, data={'arg1': vport})
        self.ixnObj.waitForComplete(response, url + '/' + response.json()['id'])