def VerifyArpNgpfPy(ipType='ipv4'):
    # This API requires:
    #    1> DeviceGroupProtocolStacksNgpfPy
    #
    # ipType:  ipv4 or ipv6
    #
    # This API will verify for ARP session resolvement on 
    # every TopologyGroup/DeviceGroup and/or
    #       TopologyGroup/DeviceGroup/DeviceGroup that has protocol "enabled".
    # 
    # How it works?
    #    Each device group has a list of $sessionStatus: up, down or notStarted.
    #    If the deviceGroup has sessionStatus as "up", then ARP will be verified.
    #    It also has a list of $resolvedGatewayMac: MacAddress or removePacket[Unresolved]
    #    These two lists are aligned.
    #    If lindex 0 on $sessionSatus is up, then the API expects lindex 0 on $resolvedGatewayMac 
    #    to have a mac address.
    #    If not, then arp is not resolved.
    #    This script will wait up to the $maxRetry before it declares failed.
    #
    # Return 0 if ARP passes.
    # Return 1 if device group is not started
    # Return a list of unresolved ARPs

    startFlag = 0
    unresolvedArpList = []
    for topology in ixNet.getList(ixNet.getRoot(), 'topology'):
        for deviceGroup in ixNet.getList(topology, 'deviceGroup'):
            print '\n', deviceGroup
            deviceGroupStatus = ixNet.getAttribute(deviceGroup, '-status')
            print '\tdeviceGroup status:', deviceGroupStatus
            if deviceGroupStatus == 'started':
                startFlag = 1
                arpResult = DeviceGroupProtocolStackNgpfPy(deviceGroup, ipType)
                if arpResult != 0:
                    unresolvedArpList = unresolvedArpList + arpResult
                
                if ixNet.getList(deviceGroup, 'deviceGroup') != '':
                    for innerDeviceGroup in ixNet.getList(deviceGroup, 'deviceGroup'):
                        print '\n', innerDeviceGroup
                        arpResult = DeviceGroupProtocolStackNgpfPy(innerDeviceGroup, ipType)
                        if arpResult != 0:
                            unresolvedArpList = unresolvedArpList + arpResult
            elif ixNet.getAttribute(deviceGroup, '-status') == 'mixed':
                startFlag = 1
                print '\tWarning: Ethernet stack is started, but layer3 is not started'
                arpResult = DeviceGroupProtocolStackNgpf(deviceGroup, ipType)
                if arpResult != 0:
                    unresolvedArpList = unresolvedArpList + arpResult
                    
                if ixNet.getList(deviceGroup, 'deviceGroup') != '':
                    for innerDeviceGroup in ixNet.getList(deviceGroup, 'deviceGroup'):
                        print '\n', innerDeviceGroup
                        deviceGroupStatus2 = ixNet.getAttribute(innerDeviceGroup, '-status')
                        if deviceGroupStatus2 == 'started':
                            arpResult = DeviceGroupProtocolStackNgpfPy(deviceGroup, ipType)
                            if arpResult != 0:
                                unresolvedArpList = unresolvedArpList + arpResult

    if unresolvedArpList == [] and startFlag == 1:
        return 0
    if unresolvedArpList == [] and startFlag == 0:
        return 1
    if unresolvedArpList != [] and startFlag == 1:
        print '\n'
        for unresolvedArp in unresolvedArpList:
            print 'UnresolvedArps:', unresolvedArp
        print '\n'
        return unresolvedArpList