diff --git a/rw_core/core/api/grpc_nbi_handler.go b/rw_core/core/api/grpc_nbi_handler.go
new file mode 100755
index 0000000..1c296dd
--- /dev/null
+++ b/rw_core/core/api/grpc_nbi_handler.go
@@ -0,0 +1,807 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package api
+
+import (
+	"context"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"github.com/golang/protobuf/ptypes/empty"
+	da "github.com/opencord/voltha-go/common/core/northbound/grpc"
+	"github.com/opencord/voltha-go/rw_core/core/adapter"
+	"github.com/opencord/voltha-go/rw_core/core/device"
+	"github.com/opencord/voltha-lib-go/v3/pkg/log"
+	"github.com/opencord/voltha-lib-go/v3/pkg/version"
+	"github.com/opencord/voltha-protos/v3/go/common"
+	"github.com/opencord/voltha-protos/v3/go/omci"
+	"github.com/opencord/voltha-protos/v3/go/openflow_13"
+	"github.com/opencord/voltha-protos/v3/go/voltha"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"io"
+	"sync"
+)
+
+// Image related constants
+const (
+	ImageDownload       = iota
+	CancelImageDownload = iota
+	ActivateImage       = iota
+	RevertImage         = iota
+)
+
+// NBIHandler represent attributes of API handler
+type NBIHandler struct {
+	deviceMgr            *device.Manager
+	logicalDeviceMgr     *device.LogicalManager
+	adapterMgr           *adapter.Manager
+	packetInQueue        chan openflow_13.PacketIn
+	changeEventQueue     chan openflow_13.ChangeEvent
+	packetInQueueDone    chan bool
+	changeEventQueueDone chan bool
+	da.DefaultAPIHandler
+}
+
+// NewAPIHandler creates API handler instance
+func NewAPIHandler(deviceMgr *device.Manager, logicalDeviceMgr *device.LogicalManager, adapterMgr *adapter.Manager) *NBIHandler {
+	return &NBIHandler{
+		deviceMgr:            deviceMgr,
+		logicalDeviceMgr:     logicalDeviceMgr,
+		adapterMgr:           adapterMgr,
+		packetInQueue:        make(chan openflow_13.PacketIn, 100),
+		changeEventQueue:     make(chan openflow_13.ChangeEvent, 100),
+		packetInQueueDone:    make(chan bool, 1),
+		changeEventQueueDone: make(chan bool, 1),
+	}
+}
+
+// waitForNilResponseOnSuccess is a helper function to wait for a response on channel monitorCh where an nil
+// response is expected in a successful scenario
+func waitForNilResponseOnSuccess(ctx context.Context, ch chan interface{}) (*empty.Empty, error) {
+	select {
+	case res := <-ch:
+		if res == nil {
+			return &empty.Empty{}, nil
+		} else if err, ok := res.(error); ok {
+			return &empty.Empty{}, err
+		} else {
+			logger.Warnw("unexpected-return-type", log.Fields{"result": res})
+			err = status.Errorf(codes.Internal, "%s", res)
+			return &empty.Empty{}, err
+		}
+	case <-ctx.Done():
+		logger.Debug("client-timeout")
+		return nil, ctx.Err()
+	}
+}
+
+// ListCoreInstances returns details on the running core containers
+func (handler *NBIHandler) ListCoreInstances(ctx context.Context, empty *empty.Empty) (*voltha.CoreInstances, error) {
+	logger.Debug("ListCoreInstances")
+	// TODO: unused stub
+	return &voltha.CoreInstances{}, status.Errorf(codes.NotFound, "no-core-instances")
+}
+
+// GetCoreInstance returns the details of a specific core container
+func (handler *NBIHandler) GetCoreInstance(ctx context.Context, id *voltha.ID) (*voltha.CoreInstance, error) {
+	logger.Debugw("GetCoreInstance", log.Fields{"id": id})
+	//TODO: unused stub
+	return &voltha.CoreInstance{}, status.Errorf(codes.NotFound, "core-instance-%s", id.Id)
+}
+
+// GetLogicalDevicePort returns logical device port details
+func (handler *NBIHandler) GetLogicalDevicePort(ctx context.Context, id *voltha.LogicalPortId) (*voltha.LogicalPort, error) {
+	logger.Debugw("GetLogicalDevicePort-request", log.Fields{"id": *id})
+
+	return handler.logicalDeviceMgr.GetLogicalPort(ctx, id)
+}
+
+// EnableLogicalDevicePort enables logical device port
+func (handler *NBIHandler) EnableLogicalDevicePort(ctx context.Context, id *voltha.LogicalPortId) (*empty.Empty, error) {
+	logger.Debugw("EnableLogicalDevicePort-request", log.Fields{"id": id, "test": common.TestModeKeys_api_test.String()})
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.logicalDeviceMgr.EnableLogicalPort(ctx, id, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// DisableLogicalDevicePort disables logical device port
+func (handler *NBIHandler) DisableLogicalDevicePort(ctx context.Context, id *voltha.LogicalPortId) (*empty.Empty, error) {
+	logger.Debugw("DisableLogicalDevicePort-request", log.Fields{"id": id, "test": common.TestModeKeys_api_test.String()})
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.logicalDeviceMgr.DisableLogicalPort(ctx, id, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// UpdateLogicalDeviceFlowTable updates logical device flow table
+func (handler *NBIHandler) UpdateLogicalDeviceFlowTable(ctx context.Context, flow *openflow_13.FlowTableUpdate) (*empty.Empty, error) {
+	logger.Debugw("UpdateLogicalDeviceFlowTable-request", log.Fields{"flow": flow, "test": common.TestModeKeys_api_test.String()})
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.logicalDeviceMgr.UpdateFlowTable(ctx, flow.Id, flow.FlowMod, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// UpdateLogicalDeviceFlowGroupTable updates logical device flow group table
+func (handler *NBIHandler) UpdateLogicalDeviceFlowGroupTable(ctx context.Context, flow *openflow_13.FlowGroupTableUpdate) (*empty.Empty, error) {
+	logger.Debugw("UpdateLogicalDeviceFlowGroupTable-request", log.Fields{"flow": flow, "test": common.TestModeKeys_api_test.String()})
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.logicalDeviceMgr.UpdateGroupTable(ctx, flow.Id, flow.GroupMod, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// GetDevice must be implemented in the read-only containers - should it also be implemented here?
+func (handler *NBIHandler) GetDevice(ctx context.Context, id *voltha.ID) (*voltha.Device, error) {
+	logger.Debugw("GetDevice-request", log.Fields{"id": id})
+	return handler.deviceMgr.GetDevice(ctx, id.Id)
+}
+
+// GetDevice must be implemented in the read-only containers - should it also be implemented here?
+
+// ListDevices retrieves the latest devices from the data model
+func (handler *NBIHandler) ListDevices(ctx context.Context, empty *empty.Empty) (*voltha.Devices, error) {
+	logger.Debug("ListDevices")
+	devices, err := handler.deviceMgr.ListDevices(ctx)
+	if err != nil {
+		logger.Errorw("Failed to list devices", log.Fields{"error": err})
+		return nil, err
+	}
+	return devices, nil
+}
+
+// ListDeviceIds returns the list of device ids managed by a voltha core
+func (handler *NBIHandler) ListDeviceIds(ctx context.Context, empty *empty.Empty) (*voltha.IDs, error) {
+	logger.Debug("ListDeviceIDs")
+	return handler.deviceMgr.ListDeviceIds()
+}
+
+//ReconcileDevices is a request to a voltha core to managed a list of devices  based on their IDs
+func (handler *NBIHandler) ReconcileDevices(ctx context.Context, ids *voltha.IDs) (*empty.Empty, error) {
+	logger.Debug("ReconcileDevices")
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.ReconcileDevices(ctx, ids, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// GetLogicalDevice provides a cloned most up to date logical device
+func (handler *NBIHandler) GetLogicalDevice(ctx context.Context, id *voltha.ID) (*voltha.LogicalDevice, error) {
+	logger.Debugw("GetLogicalDevice-request", log.Fields{"id": id})
+	return handler.logicalDeviceMgr.GetLogicalDevice(ctx, id.Id)
+}
+
+// ListLogicalDevices returns the list of all logical devices
+func (handler *NBIHandler) ListLogicalDevices(ctx context.Context, empty *empty.Empty) (*voltha.LogicalDevices, error) {
+	logger.Debug("ListLogicalDevices-request")
+	return handler.logicalDeviceMgr.ListLogicalDevices(ctx)
+}
+
+// ListAdapters returns the contents of all adapters known to the system
+func (handler *NBIHandler) ListAdapters(ctx context.Context, empty *empty.Empty) (*voltha.Adapters, error) {
+	logger.Debug("ListAdapters")
+	return handler.adapterMgr.ListAdapters(ctx)
+}
+
+// ListLogicalDeviceFlows returns the flows of logical device
+func (handler *NBIHandler) ListLogicalDeviceFlows(ctx context.Context, id *voltha.ID) (*openflow_13.Flows, error) {
+	logger.Debugw("ListLogicalDeviceFlows", log.Fields{"id": *id})
+	return handler.logicalDeviceMgr.ListLogicalDeviceFlows(ctx, id.Id)
+}
+
+// ListLogicalDeviceFlowGroups returns logical device flow groups
+func (handler *NBIHandler) ListLogicalDeviceFlowGroups(ctx context.Context, id *voltha.ID) (*openflow_13.FlowGroups, error) {
+	logger.Debugw("ListLogicalDeviceFlowGroups", log.Fields{"id": *id})
+	return handler.logicalDeviceMgr.ListLogicalDeviceFlowGroups(ctx, id.Id)
+}
+
+// ListLogicalDevicePorts returns ports of logical device
+func (handler *NBIHandler) ListLogicalDevicePorts(ctx context.Context, id *voltha.ID) (*voltha.LogicalPorts, error) {
+	logger.Debugw("ListLogicalDevicePorts", log.Fields{"logicaldeviceid": id})
+	return handler.logicalDeviceMgr.ListLogicalDevicePorts(ctx, id.Id)
+}
+
+// CreateDevice creates a new parent device in the data model
+func (handler *NBIHandler) CreateDevice(ctx context.Context, device *voltha.Device) (*voltha.Device, error) {
+	if device.MacAddress == "" && device.GetHostAndPort() == "" {
+		logger.Errorf("No Device Info Present")
+		return &voltha.Device{}, errors.New("no-device-info-present; MAC or HOSTIP&PORT")
+	}
+	logger.Debugw("create-device", log.Fields{"device": *device})
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.CreateDevice(ctx, device, ch)
+	select {
+	case res := <-ch:
+		if res != nil {
+			if err, ok := res.(error); ok {
+				logger.Errorw("create-device-failed", log.Fields{"error": err})
+				return nil, err
+			}
+			if d, ok := res.(*voltha.Device); ok {
+				return d, nil
+			}
+		}
+		logger.Warnw("create-device-unexpected-return-type", log.Fields{"result": res})
+		err := status.Errorf(codes.Internal, "%s", res)
+		return &voltha.Device{}, err
+	case <-ctx.Done():
+		logger.Debug("createdevice-client-timeout")
+		return &voltha.Device{}, ctx.Err()
+	}
+}
+
+// EnableDevice activates a device by invoking the adopt_device API on the appropriate adapter
+func (handler *NBIHandler) EnableDevice(ctx context.Context, id *voltha.ID) (*empty.Empty, error) {
+	logger.Debugw("enabledevice", log.Fields{"id": id})
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.EnableDevice(ctx, id, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// DisableDevice disables a device along with any child device it may have
+func (handler *NBIHandler) DisableDevice(ctx context.Context, id *voltha.ID) (*empty.Empty, error) {
+	logger.Debugw("disabledevice-request", log.Fields{"id": id})
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.DisableDevice(ctx, id, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+//RebootDevice invoked the reboot API to the corresponding adapter
+func (handler *NBIHandler) RebootDevice(ctx context.Context, id *voltha.ID) (*empty.Empty, error) {
+	logger.Debugw("rebootDevice-request", log.Fields{"id": id})
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.RebootDevice(ctx, id, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// DeleteDevice removes a device from the data model
+func (handler *NBIHandler) DeleteDevice(ctx context.Context, id *voltha.ID) (*empty.Empty, error) {
+	logger.Debugw("deletedevice-request", log.Fields{"id": id})
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.DeleteDevice(ctx, id, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// ListDevicePorts returns the ports details for a specific device entry
+func (handler *NBIHandler) ListDevicePorts(ctx context.Context, id *voltha.ID) (*voltha.Ports, error) {
+	logger.Debugw("listdeviceports-request", log.Fields{"id": id})
+	device, err := handler.deviceMgr.GetDevice(ctx, id.Id)
+	if err != nil {
+		return &voltha.Ports{}, err
+	}
+	ports := &voltha.Ports{}
+	ports.Items = append(ports.Items, device.Ports...)
+	return ports, nil
+}
+
+// ListDeviceFlows returns the flow details for a specific device entry
+func (handler *NBIHandler) ListDeviceFlows(ctx context.Context, id *voltha.ID) (*openflow_13.Flows, error) {
+	logger.Debugw("listdeviceflows-request", log.Fields{"id": id})
+
+	device, err := handler.deviceMgr.GetDevice(ctx, id.Id)
+	if err != nil {
+		return &openflow_13.Flows{}, err
+	}
+	flows := &openflow_13.Flows{}
+	flows.Items = append(flows.Items, device.Flows.Items...)
+	return flows, nil
+}
+
+// ListDeviceFlowGroups returns the flow group details for a specific device entry
+func (handler *NBIHandler) ListDeviceFlowGroups(ctx context.Context, id *voltha.ID) (*voltha.FlowGroups, error) {
+	logger.Debugw("ListDeviceFlowGroups", log.Fields{"deviceid": id})
+
+	if device, _ := handler.deviceMgr.GetDevice(ctx, id.Id); device != nil {
+		return device.GetFlowGroups(), nil
+	}
+	return &voltha.FlowGroups{}, status.Errorf(codes.NotFound, "device-%s", id.Id)
+}
+
+// ListDeviceGroups returns all the device groups known to the system
+func (handler *NBIHandler) ListDeviceGroups(ctx context.Context, empty *empty.Empty) (*voltha.DeviceGroups, error) {
+	logger.Debug("ListDeviceGroups")
+	return &voltha.DeviceGroups{}, errors.New("UnImplemented")
+}
+
+// GetDeviceGroup returns a specific device group entry
+func (handler *NBIHandler) GetDeviceGroup(ctx context.Context, id *voltha.ID) (*voltha.DeviceGroup, error) {
+	logger.Debug("GetDeviceGroup")
+	return &voltha.DeviceGroup{}, errors.New("UnImplemented")
+}
+
+// ListDeviceTypes returns all the device types known to the system
+func (handler *NBIHandler) ListDeviceTypes(ctx context.Context, _ *empty.Empty) (*voltha.DeviceTypes, error) {
+	logger.Debug("ListDeviceTypes")
+
+	return &voltha.DeviceTypes{Items: handler.adapterMgr.ListDeviceTypes()}, nil
+}
+
+// GetDeviceType returns the device type for a specific device entry
+func (handler *NBIHandler) GetDeviceType(ctx context.Context, id *voltha.ID) (*voltha.DeviceType, error) {
+	logger.Debugw("GetDeviceType", log.Fields{"typeid": id})
+
+	if deviceType := handler.adapterMgr.GetDeviceType(id.Id); deviceType != nil {
+		return deviceType, nil
+	}
+	return &voltha.DeviceType{}, status.Errorf(codes.NotFound, "device_type-%s", id.Id)
+}
+
+// GetVoltha returns the contents of all components (i.e. devices, logical_devices, ...)
+func (handler *NBIHandler) GetVoltha(ctx context.Context, empty *empty.Empty) (*voltha.Voltha, error) {
+
+	logger.Debug("GetVoltha")
+	/*
+	 * For now, encode all the version information into a JSON object and
+	 * pass that back as "version" so the client can get all the
+	 * information associated with the version. Long term the API should
+	 * better accomidate this, but for now this will work.
+	 */
+	data, err := json.Marshal(&version.VersionInfo)
+	info := version.VersionInfo.Version
+	if err != nil {
+		logger.Warnf("Unable to encode version information as JSON: %s", err.Error())
+	} else {
+		info = string(data)
+	}
+
+	return &voltha.Voltha{
+		Version: info,
+	}, nil
+}
+
+// processImageRequest is a helper method to execute an image download request
+func (handler *NBIHandler) processImageRequest(ctx context.Context, img *voltha.ImageDownload, requestType int) (*common.OperationResp, error) {
+	logger.Debugw("processImageDownload", log.Fields{"img": *img, "requestType": requestType})
+
+	failedresponse := &common.OperationResp{Code: voltha.OperationResp_OPERATION_FAILURE}
+
+	ch := make(chan interface{})
+	defer close(ch)
+	switch requestType {
+	case ImageDownload:
+		go handler.deviceMgr.DownloadImage(ctx, img, ch)
+	case CancelImageDownload:
+		go handler.deviceMgr.CancelImageDownload(ctx, img, ch)
+	case ActivateImage:
+		go handler.deviceMgr.ActivateImage(ctx, img, ch)
+	case RevertImage:
+		go handler.deviceMgr.RevertImage(ctx, img, ch)
+	default:
+		logger.Warn("invalid-request-type", log.Fields{"requestType": requestType})
+		return failedresponse, status.Errorf(codes.InvalidArgument, "%d", requestType)
+	}
+	select {
+	case res := <-ch:
+		if res != nil {
+			if err, ok := res.(error); ok {
+				return failedresponse, err
+			}
+			if opResp, ok := res.(*common.OperationResp); ok {
+				return opResp, nil
+			}
+		}
+		logger.Warnw("download-image-unexpected-return-type", log.Fields{"result": res})
+		return failedresponse, status.Errorf(codes.Internal, "%s", res)
+	case <-ctx.Done():
+		logger.Debug("downloadImage-client-timeout")
+		return &common.OperationResp{}, ctx.Err()
+	}
+}
+
+// DownloadImage execute an image download request
+func (handler *NBIHandler) DownloadImage(ctx context.Context, img *voltha.ImageDownload) (*common.OperationResp, error) {
+	logger.Debugw("DownloadImage-request", log.Fields{"img": *img})
+
+	return handler.processImageRequest(ctx, img, ImageDownload)
+}
+
+// CancelImageDownload cancels image download request
+func (handler *NBIHandler) CancelImageDownload(ctx context.Context, img *voltha.ImageDownload) (*common.OperationResp, error) {
+	logger.Debugw("cancelImageDownload-request", log.Fields{"img": *img})
+	return handler.processImageRequest(ctx, img, CancelImageDownload)
+}
+
+// ActivateImageUpdate activates image update request
+func (handler *NBIHandler) ActivateImageUpdate(ctx context.Context, img *voltha.ImageDownload) (*common.OperationResp, error) {
+	logger.Debugw("activateImageUpdate-request", log.Fields{"img": *img})
+	return handler.processImageRequest(ctx, img, ActivateImage)
+}
+
+// RevertImageUpdate reverts image update
+func (handler *NBIHandler) RevertImageUpdate(ctx context.Context, img *voltha.ImageDownload) (*common.OperationResp, error) {
+	logger.Debugw("revertImageUpdate-request", log.Fields{"img": *img})
+	return handler.processImageRequest(ctx, img, RevertImage)
+}
+
+// GetImageDownloadStatus returns status of image download
+func (handler *NBIHandler) GetImageDownloadStatus(ctx context.Context, img *voltha.ImageDownload) (*voltha.ImageDownload, error) {
+	logger.Debugw("getImageDownloadStatus-request", log.Fields{"img": *img})
+
+	failedresponse := &voltha.ImageDownload{DownloadState: voltha.ImageDownload_DOWNLOAD_UNKNOWN}
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.GetImageDownloadStatus(ctx, img, ch)
+
+	select {
+	case res := <-ch:
+		if res != nil {
+			if err, ok := res.(error); ok {
+				return failedresponse, err
+			}
+			if downloadResp, ok := res.(*voltha.ImageDownload); ok {
+				return downloadResp, nil
+			}
+		}
+		logger.Warnw("download-image-status", log.Fields{"result": res})
+		return failedresponse, status.Errorf(codes.Internal, "%s", res)
+	case <-ctx.Done():
+		logger.Debug("downloadImage-client-timeout")
+		return failedresponse, ctx.Err()
+	}
+}
+
+// GetImageDownload returns image download
+func (handler *NBIHandler) GetImageDownload(ctx context.Context, img *voltha.ImageDownload) (*voltha.ImageDownload, error) {
+	logger.Debugw("GetImageDownload-request", log.Fields{"img": *img})
+
+	download, err := handler.deviceMgr.GetImageDownload(ctx, img)
+	if err != nil {
+		return &voltha.ImageDownload{DownloadState: voltha.ImageDownload_DOWNLOAD_UNKNOWN}, err
+	}
+	return download, nil
+}
+
+// ListImageDownloads returns image downloads
+func (handler *NBIHandler) ListImageDownloads(ctx context.Context, id *voltha.ID) (*voltha.ImageDownloads, error) {
+	logger.Debugw("ListImageDownloads-request", log.Fields{"deviceId": id.Id})
+
+	downloads, err := handler.deviceMgr.ListImageDownloads(ctx, id.Id)
+	if err != nil {
+		failedResp := &voltha.ImageDownloads{
+			Items: []*voltha.ImageDownload{
+				{DownloadState: voltha.ImageDownload_DOWNLOAD_UNKNOWN},
+			},
+		}
+		return failedResp, err
+	}
+	return downloads, nil
+}
+
+// GetImages returns all images for a specific device entry
+func (handler *NBIHandler) GetImages(ctx context.Context, id *voltha.ID) (*voltha.Images, error) {
+	logger.Debugw("GetImages", log.Fields{"deviceid": id.Id})
+	device, err := handler.deviceMgr.GetDevice(ctx, id.Id)
+	if err != nil {
+		return &voltha.Images{}, err
+	}
+	return device.GetImages(), nil
+}
+
+// UpdateDevicePmConfigs updates the PM configs
+func (handler *NBIHandler) UpdateDevicePmConfigs(ctx context.Context, configs *voltha.PmConfigs) (*empty.Empty, error) {
+	logger.Debugw("UpdateDevicePmConfigs-request", log.Fields{"configs": *configs})
+
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.UpdatePmConfigs(ctx, configs, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// ListDevicePmConfigs returns pm configs of device
+func (handler *NBIHandler) ListDevicePmConfigs(ctx context.Context, id *voltha.ID) (*voltha.PmConfigs, error) {
+	logger.Debugw("ListDevicePmConfigs-request", log.Fields{"deviceId": *id})
+	return handler.deviceMgr.ListPmConfigs(ctx, id.Id)
+}
+
+func (handler *NBIHandler) CreateEventFilter(ctx context.Context, filter *voltha.EventFilter) (*voltha.EventFilter, error) {
+	logger.Debugw("CreateEventFilter-request", log.Fields{"filter": *filter})
+	return nil, errors.New("UnImplemented")
+}
+
+func (handler *NBIHandler) UpdateEventFilter(ctx context.Context, filter *voltha.EventFilter) (*voltha.EventFilter, error) {
+	logger.Debugw("UpdateEventFilter-request", log.Fields{"filter": *filter})
+	return nil, errors.New("UnImplemented")
+}
+
+func (handler *NBIHandler) DeleteEventFilter(ctx context.Context, filterInfo *voltha.EventFilter) (*empty.Empty, error) {
+	logger.Debugw("DeleteEventFilter-request", log.Fields{"device-id": filterInfo.DeviceId, "filter-id": filterInfo.Id})
+	return nil, errors.New("UnImplemented")
+}
+
+// GetEventFilter returns all the filters present for a device
+func (handler *NBIHandler) GetEventFilter(ctx context.Context, id *voltha.ID) (*voltha.EventFilters, error) {
+	logger.Debugw("GetEventFilter-request", log.Fields{"device-id": id})
+	return nil, errors.New("UnImplemented")
+}
+
+// ListEventFilters returns all the filters known to the system
+func (handler *NBIHandler) ListEventFilters(ctx context.Context, empty *empty.Empty) (*voltha.EventFilters, error) {
+	logger.Debug("ListEventFilter-request")
+	return nil, errors.New("UnImplemented")
+}
+
+func (handler *NBIHandler) SelfTest(ctx context.Context, id *voltha.ID) (*voltha.SelfTestResponse, error) {
+	logger.Debugw("SelfTest-request", log.Fields{"id": id})
+	return &voltha.SelfTestResponse{}, errors.New("UnImplemented")
+}
+
+// StreamPacketsOut sends packets to adapter
+func (handler *NBIHandler) StreamPacketsOut(packets voltha.VolthaService_StreamPacketsOutServer) error {
+	logger.Debugw("StreamPacketsOut-request", log.Fields{"packets": packets})
+loop:
+	for {
+		select {
+		case <-packets.Context().Done():
+			logger.Infow("StreamPacketsOut-context-done", log.Fields{"packets": packets, "error": packets.Context().Err()})
+			break loop
+		default:
+		}
+
+		packet, err := packets.Recv()
+
+		if err == io.EOF {
+			logger.Debugw("Received-EOF", log.Fields{"packets": packets})
+			break loop
+		}
+
+		if err != nil {
+			logger.Errorw("Failed to receive packet out", log.Fields{"error": err})
+			continue
+		}
+
+		handler.logicalDeviceMgr.PacketOut(packets.Context(), packet)
+	}
+
+	logger.Debugw("StreamPacketsOut-request-done", log.Fields{"packets": packets})
+	return nil
+}
+
+func (handler *NBIHandler) SendPacketIn(deviceID string, transationID string, packet *openflow_13.OfpPacketIn) {
+	// TODO: Augment the OF PacketIn to include the transactionId
+	packetIn := openflow_13.PacketIn{Id: deviceID, PacketIn: packet}
+	logger.Debugw("SendPacketIn", log.Fields{"packetIn": packetIn})
+	handler.packetInQueue <- packetIn
+}
+
+type callTracker struct {
+	failedPacket interface{}
+}
+type streamTracker struct {
+	calls map[string]*callTracker
+	sync.Mutex
+}
+
+var streamingTracker = &streamTracker{calls: make(map[string]*callTracker)}
+
+func (handler *NBIHandler) getStreamingTracker(method string, done chan<- bool) *callTracker {
+	streamingTracker.Lock()
+	defer streamingTracker.Unlock()
+	if _, ok := streamingTracker.calls[method]; ok {
+		// bail out the other packet in thread
+		logger.Debugf("%s streaming call already running. Exiting it", method)
+		done <- true
+		logger.Debugf("Last %s exited. Continuing ...", method)
+	} else {
+		streamingTracker.calls[method] = &callTracker{failedPacket: nil}
+	}
+	return streamingTracker.calls[method]
+}
+
+func (handler *NBIHandler) flushFailedPackets(tracker *callTracker) error {
+	if tracker.failedPacket != nil {
+		switch tracker.failedPacket.(type) {
+		case openflow_13.PacketIn:
+			logger.Debug("Enqueueing last failed packetIn")
+			handler.packetInQueue <- tracker.failedPacket.(openflow_13.PacketIn)
+		case openflow_13.ChangeEvent:
+			logger.Debug("Enqueueing last failed changeEvent")
+			handler.changeEventQueue <- tracker.failedPacket.(openflow_13.ChangeEvent)
+		}
+	}
+	return nil
+}
+
+// ReceivePacketsIn receives packets from adapter
+func (handler *NBIHandler) ReceivePacketsIn(empty *empty.Empty, packetsIn voltha.VolthaService_ReceivePacketsInServer) error {
+	var streamingTracker = handler.getStreamingTracker("ReceivePacketsIn", handler.packetInQueueDone)
+	logger.Debugw("ReceivePacketsIn-request", log.Fields{"packetsIn": packetsIn})
+
+	err := handler.flushFailedPackets(streamingTracker)
+	if err != nil {
+		logger.Errorw("unable-to-flush-failed-packets", log.Fields{"error": err})
+	}
+
+loop:
+	for {
+		select {
+		case packet := <-handler.packetInQueue:
+			logger.Debugw("sending-packet-in", log.Fields{
+				"packet": hex.EncodeToString(packet.PacketIn.Data),
+			})
+			if err := packetsIn.Send(&packet); err != nil {
+				logger.Errorw("failed-to-send-packet", log.Fields{"error": err})
+				// save the last failed packet in
+				streamingTracker.failedPacket = packet
+			} else {
+				if streamingTracker.failedPacket != nil {
+					// reset last failed packet saved to avoid flush
+					streamingTracker.failedPacket = nil
+				}
+			}
+		case <-handler.packetInQueueDone:
+			logger.Debug("Another ReceivePacketsIn running. Bailing out ...")
+			break loop
+		}
+	}
+
+	//TODO: Find an elegant way to get out of the above loop when the Core is stopped
+	return nil
+}
+
+func (handler *NBIHandler) SendChangeEvent(deviceID string, portStatus *openflow_13.OfpPortStatus) {
+	// TODO: validate the type of portStatus parameter
+	//if _, ok := portStatus.(*openflow_13.OfpPortStatus); ok {
+	//}
+	event := openflow_13.ChangeEvent{Id: deviceID, Event: &openflow_13.ChangeEvent_PortStatus{PortStatus: portStatus}}
+	logger.Debugw("SendChangeEvent", log.Fields{"event": event})
+	handler.changeEventQueue <- event
+}
+
+// ReceiveChangeEvents receives change in events
+func (handler *NBIHandler) ReceiveChangeEvents(empty *empty.Empty, changeEvents voltha.VolthaService_ReceiveChangeEventsServer) error {
+	var streamingTracker = handler.getStreamingTracker("ReceiveChangeEvents", handler.changeEventQueueDone)
+	logger.Debugw("ReceiveChangeEvents-request", log.Fields{"changeEvents": changeEvents})
+
+	err := handler.flushFailedPackets(streamingTracker)
+	if err != nil {
+		logger.Errorw("unable-to-flush-failed-packets", log.Fields{"error": err})
+	}
+
+loop:
+	for {
+		select {
+		// Dequeue a change event
+		case event := <-handler.changeEventQueue:
+			logger.Debugw("sending-change-event", log.Fields{"event": event})
+			if err := changeEvents.Send(&event); err != nil {
+				logger.Errorw("failed-to-send-change-event", log.Fields{"error": err})
+				// save last failed changeevent
+				streamingTracker.failedPacket = event
+			} else {
+				if streamingTracker.failedPacket != nil {
+					// reset last failed event saved on success to avoid flushing
+					streamingTracker.failedPacket = nil
+				}
+			}
+		case <-handler.changeEventQueueDone:
+			logger.Debug("Another ReceiveChangeEvents already running. Bailing out ...")
+			break loop
+		}
+	}
+
+	return nil
+}
+
+func (handler *NBIHandler) GetChangeEventsQueueForTest() <-chan openflow_13.ChangeEvent {
+	return handler.changeEventQueue
+}
+
+// Subscribe subscribing request of ofagent
+func (handler *NBIHandler) Subscribe(
+	ctx context.Context,
+	ofAgent *voltha.OfAgentSubscriber,
+) (*voltha.OfAgentSubscriber, error) {
+	logger.Debugw("Subscribe-request", log.Fields{"ofAgent": ofAgent})
+	return &voltha.OfAgentSubscriber{OfagentId: ofAgent.OfagentId, VolthaId: ofAgent.VolthaId}, nil
+}
+
+// GetAlarmDeviceData @TODO useless stub, what should this actually do?
+func (handler *NBIHandler) GetAlarmDeviceData(ctx context.Context, in *common.ID) (*omci.AlarmDeviceData, error) {
+	logger.Debug("GetAlarmDeviceData-stub")
+	return &omci.AlarmDeviceData{}, errors.New("UnImplemented")
+}
+
+// ListLogicalDeviceMeters returns logical device meters
+func (handler *NBIHandler) ListLogicalDeviceMeters(ctx context.Context, id *voltha.ID) (*openflow_13.Meters, error) {
+
+	logger.Debugw("ListLogicalDeviceMeters", log.Fields{"id": *id})
+	return handler.logicalDeviceMgr.ListLogicalDeviceMeters(ctx, id.Id)
+}
+
+// GetMeterStatsOfLogicalDevice @TODO useless stub, what should this actually do?
+func (handler *NBIHandler) GetMeterStatsOfLogicalDevice(ctx context.Context, in *common.ID) (*openflow_13.MeterStatsReply, error) {
+	logger.Debug("GetMeterStatsOfLogicalDevice")
+	return &openflow_13.MeterStatsReply{}, errors.New("UnImplemented")
+}
+
+// GetMibDeviceData @TODO useless stub, what should this actually do?
+func (handler *NBIHandler) GetMibDeviceData(ctx context.Context, in *common.ID) (*omci.MibDeviceData, error) {
+	logger.Debug("GetMibDeviceData")
+	return &omci.MibDeviceData{}, errors.New("UnImplemented")
+}
+
+// SimulateAlarm sends simulate alarm request
+func (handler *NBIHandler) SimulateAlarm(
+	ctx context.Context,
+	in *voltha.SimulateAlarmRequest,
+) (*common.OperationResp, error) {
+	logger.Debugw("SimulateAlarm-request", log.Fields{"id": in.Id})
+	successResp := &common.OperationResp{Code: common.OperationResp_OPERATION_SUCCESS}
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.SimulateAlarm(ctx, in, ch)
+	return successResp, nil
+}
+
+// UpdateLogicalDeviceMeterTable - This function sends meter mod request to logical device manager and waits for response
+func (handler *NBIHandler) UpdateLogicalDeviceMeterTable(ctx context.Context, meter *openflow_13.MeterModUpdate) (*empty.Empty, error) {
+	logger.Debugw("UpdateLogicalDeviceMeterTable-request",
+		log.Fields{"meter": meter, "test": common.TestModeKeys_api_test.String()})
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.logicalDeviceMgr.UpdateMeterTable(ctx, meter.Id, meter.MeterMod, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+// GetMembership returns membership
+func (handler *NBIHandler) GetMembership(context.Context, *empty.Empty) (*voltha.Membership, error) {
+	return &voltha.Membership{}, errors.New("UnImplemented")
+}
+
+// UpdateMembership updates membership
+func (handler *NBIHandler) UpdateMembership(context.Context, *voltha.Membership) (*empty.Empty, error) {
+	return &empty.Empty{}, errors.New("UnImplemented")
+}
+
+func (handler *NBIHandler) EnablePort(ctx context.Context, port *voltha.Port) (*empty.Empty, error) {
+	logger.Debugw("EnablePort-request", log.Fields{"device-id": port.DeviceId, "port-no": port.PortNo})
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.EnablePort(ctx, port, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+func (handler *NBIHandler) DisablePort(ctx context.Context, port *voltha.Port) (*empty.Empty, error) {
+
+	logger.Debugw("DisablePort-request", log.Fields{"device-id": port.DeviceId, "port-no": port.PortNo})
+	ch := make(chan interface{})
+	defer close(ch)
+	go handler.deviceMgr.DisablePort(ctx, port, ch)
+	return waitForNilResponseOnSuccess(ctx, ch)
+}
+
+func (handler *NBIHandler) StartOmciTestAction(ctx context.Context, omcitestrequest *voltha.OmciTestRequest) (*voltha.TestResponse, error) {
+	logger.Debugw("Omci_test_Request", log.Fields{"id": omcitestrequest.Id, "uuid": omcitestrequest.Uuid})
+	return handler.deviceMgr.StartOmciTest(ctx, omcitestrequest)
+}