def sendIgmpJoinLeaveNgpf(self, routerId=None, igmpHostUrl=None, multicastIpAddress=None, action='join'):
        """
        Description
            Send IGMP joins or leaves.

            A IGMP host object is acceptable.  If you don't know the IGMP host object, use Device Group RouterID.
            Since a Device Group could have many routerID, you could state one of them.

            If multicastIpAddress is 'all', this will send IGMP join on all multicast addresses.
            Else, provide a list of multicast IP addresses to send join.

        Parameters
            routerId: The Device Group Router ID address.
            igmpHostUrl: '/api/v1/sessions/1/ixnetwork/topology/1/deviceGroup/1/ethernet/1/ipv4/1/igmpHost/1'
            multicastIpAddress: 'all' or a list of multicast IP addresses to send join.
                                 Example: ['225.0.0.3', '225.0.0.4']
            action: join|leave
        """
        if action == 'join':
            action = 'igmpjoingroup'
        if action == 'leave':
            action = 'igmpleavegroup'

        # In case somebody passes in http://{ip:port}.  All this function needs is the Rest API.
        if igmpHostUrl:
            match = re.match('http://.*(/api.*)', igmpHostUrl)
            if match:
                igmpHostUrl = match.group(1)

        if routerId:
            deviceGroupObj = self.getDeviceGroupByRouterId(routerId=routerId)
            if deviceGroupObj == 0:
                raise IxNetRestApiException('No Device Group found for router ID: %s' % routerId)

            queryData = {'from': deviceGroupObj,
                        'nodes': [{'node': 'routerData', 'properties': [], 'where': []},
                                  {'node': 'ethernet', 'properties': [], 'where': []},
                                  {'node': 'ipv4', 'properties': [], 'where': []},
                                  {'node': 'igmpHost', 'properties': [], 'where': []},
                              ]}
            queryResponse = self.ixnObj.query(data=queryData)
            routerIdObj = queryResponse.json()['result'][0]['routerData'][0]['href']
            response = self.ixnObj.get(self.ixnObj.httpHeader+routerIdObj)
            routerIdMultivalue = response.json()['routerId']
            routerIdList = self.ixnObj.getMultivalueValues(routerIdMultivalue, silentMode=True)
            if routerId in routerIdList:
                igmpHostUrl = queryResponse.json()['result'][0]['ethernet'][0]['ipv4'][0]['igmpHost'][0]['href']

        # Based on the list of multicastIpAddress, get all their indexes.
        response = self.ixnObj.get(self.ixnObj.httpHeader+igmpHostUrl+'/igmpMcastIPv4GroupList')
        startMcastAddrMultivalue = response.json()['startMcastAddr']
        listOfConfiguredMcastIpAddresses = self.ixnObj.getMultivalueValues(startMcastAddrMultivalue)

        self.ixnObj.logInfo('sendIgmpJoinNgpf: List of configured Mcast IP addresses: %s' % listOfConfiguredMcastIpAddresses)
        if listOfConfiguredMcastIpAddresses == []:
            raise IxNetRestApiException('sendIgmpJoinNgpf: No Mcast IP address configured')

        if multicastIpAddress == 'all':
            listOfMcastAddresses = listOfConfiguredMcastIpAddresses
        else:
            listOfMcastAddresses = multicastIpAddress

        # Note: Index position is not zero based.
        indexListToSend = []
        for eachMcastAddress in listOfMcastAddresses:
            index = listOfConfiguredMcastIpAddresses.index(eachMcastAddress)
            indexListToSend.append(index+1)

        url = igmpHostUrl+'/igmpMcastIPv4GroupList/operations/%s' % action
        data = {'arg1': [igmpHostUrl+'/igmpMcastIPv4GroupList'], 'arg2': indexListToSend}
        self.ixnObj.logInfo('sendIgmpJoinNgpf: %s' % url)
        self.ixnObj.logInfo('\t%s' % multicastIpAddress)
        response = self.ixnObj.post(self.ixnObj.httpHeader+url, data=data)
        self.ixnObj.waitForComplete(response, url+response.json()['id'])