diff --git a/vendor/github.com/opencord/voltha-go/rw_core/graph/device_graph.go b/vendor/github.com/opencord/voltha-go/rw_core/graph/device_graph.go
new file mode 100644
index 0000000..376df16
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-go/rw_core/graph/device_graph.go
@@ -0,0 +1,463 @@
+/*
+ * 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 graph
+
+import (
+	"errors"
+	"fmt"
+	"github.com/gyuho/goraph"
+	"github.com/opencord/voltha-go/common/log"
+	"github.com/opencord/voltha-protos/go/voltha"
+	"strconv"
+	"strings"
+	"sync"
+)
+
+func init() {
+	log.AddPackage(log.JSON, log.WarnLevel, nil)
+}
+
+type RouteHop struct {
+	DeviceID string
+	Ingress  uint32
+	Egress   uint32
+}
+
+type OFPortLink struct {
+	Ingress uint32
+	Egress  uint32
+}
+
+type ofPortLinkToPath struct {
+	link OFPortLink
+	path []RouteHop
+}
+
+type GetDeviceFunc func(id string) (*voltha.Device, error)
+
+type DeviceGraph struct {
+	logicalDeviceId    string
+	GGraph             goraph.Graph
+	getDeviceFromModel GetDeviceFunc
+	logicalPorts       []*voltha.LogicalPort
+	rootPortsString    map[string]uint32
+	nonRootPortsString map[string]uint32
+	RootPorts          map[uint32]uint32
+	rootPortsLock      sync.RWMutex
+	Routes             map[OFPortLink][]RouteHop
+	graphBuildLock     sync.RWMutex
+	boundaryPorts      map[string]uint32
+	boundaryPortsLock  sync.RWMutex
+	cachedDevices      map[string]*voltha.Device
+	cachedDevicesLock  sync.RWMutex
+	devicesAdded       map[string]string
+	portsAdded         map[string]string
+}
+
+func NewDeviceGraph(logicalDeviceId string, getDevice GetDeviceFunc) *DeviceGraph {
+	var dg DeviceGraph
+	dg.logicalDeviceId = logicalDeviceId
+	dg.GGraph = goraph.NewGraph()
+	dg.getDeviceFromModel = getDevice
+	dg.graphBuildLock = sync.RWMutex{}
+	dg.cachedDevicesLock = sync.RWMutex{}
+	dg.rootPortsLock = sync.RWMutex{}
+	dg.devicesAdded = make(map[string]string)
+	dg.portsAdded = make(map[string]string)
+	dg.rootPortsString = make(map[string]uint32)
+	dg.nonRootPortsString = make(map[string]uint32)
+	dg.RootPorts = make(map[uint32]uint32)
+	dg.boundaryPorts = make(map[string]uint32)
+	dg.Routes = make(map[OFPortLink][]RouteHop)
+	dg.cachedDevices = make(map[string]*voltha.Device)
+	log.Debug("new device graph created ...")
+	return &dg
+}
+
+//IsRootPort returns true if the port is a root port on a logical device
+func (dg *DeviceGraph) IsRootPort(port uint32) bool {
+	dg.rootPortsLock.RLock()
+	defer dg.rootPortsLock.RUnlock()
+	_, exist := dg.RootPorts[port]
+	return exist
+}
+
+//GetDeviceNodeIds retrieves all the nodes in the device graph
+func (dg *DeviceGraph) GetDeviceNodeIds() map[string]string {
+	dg.graphBuildLock.RLock()
+	defer dg.graphBuildLock.RUnlock()
+	nodeIds := make(map[string]string)
+	nodesMap := dg.GGraph.GetNodes()
+	for id, node := range nodesMap {
+		if len(strings.Split(node.String(), ":")) != 2 { // not port node
+			nodeIds[id.String()] = id.String()
+		}
+	}
+	return nodeIds
+}
+
+//ComputeRoutes creates a device graph from the logical ports and then calculates all the routes
+//between the logical ports.  This will clear up the graph and routes if there were any.
+func (dg *DeviceGraph) ComputeRoutes(lps []*voltha.LogicalPort) {
+	if dg == nil {
+		return
+	}
+	dg.graphBuildLock.Lock()
+	defer dg.graphBuildLock.Unlock()
+
+	// Clear the graph
+	dg.reset()
+
+	dg.logicalPorts = lps
+
+	// Set the root, non-root ports and boundary ports
+	for _, lp := range lps {
+		portId := concatDeviceIdPortId(lp.DeviceId, lp.DevicePortNo)
+		if lp.RootPort {
+			dg.rootPortsString[portId] = lp.OfpPort.PortNo
+			dg.RootPorts[lp.OfpPort.PortNo] = lp.OfpPort.PortNo
+		} else {
+			dg.nonRootPortsString[portId] = lp.OfpPort.PortNo
+		}
+		dg.boundaryPorts[portId] = lp.OfpPort.PortNo
+	}
+
+	// Build the graph
+	var device *voltha.Device
+	for _, logicalPort := range dg.logicalPorts {
+		device, _ = dg.getDevice(logicalPort.DeviceId)
+		dg.GGraph = dg.addDevice(device, dg.GGraph, &dg.devicesAdded, &dg.portsAdded, dg.boundaryPorts)
+	}
+
+	dg.Routes = dg.buildRoutes()
+}
+
+// AddPort adds a port to the graph.  If the graph is empty it will just invoke ComputeRoutes function
+func (dg *DeviceGraph) AddPort(lp *voltha.LogicalPort) {
+	//  If the graph does not exist invoke ComputeRoutes.
+	if len(dg.boundaryPorts) == 0 {
+		dg.ComputeRoutes([]*voltha.LogicalPort{lp})
+		return
+	}
+
+	dg.graphBuildLock.Lock()
+	defer dg.graphBuildLock.Unlock()
+
+	portId := concatDeviceIdPortId(lp.DeviceId, lp.DevicePortNo)
+
+	//	If the port is already part of the boundary ports, do nothing
+	if dg.portExist(portId) {
+		fmt.Println("port exists")
+		return
+	}
+	// Add the device where this port is located to the device graph. If the device is already added then
+	// only the missing port will be added
+	device, _ := dg.getDevice(lp.DeviceId)
+	dg.GGraph = dg.addDevice(device, dg.GGraph, &dg.devicesAdded, &dg.portsAdded, dg.boundaryPorts)
+
+	if lp.RootPort {
+		// Compute the route from this root port to all non-root ports
+		dg.rootPortsString[portId] = lp.OfpPort.PortNo
+		dg.RootPorts[lp.OfpPort.PortNo] = lp.OfpPort.PortNo
+		dg.Routes = dg.buildPathsToAllNonRootPorts(lp)
+	} else {
+		// Compute the route from this port to all root ports
+		dg.nonRootPortsString[portId] = lp.OfpPort.PortNo
+		dg.Routes = dg.buildPathsToAllRootPorts(lp)
+	}
+
+	dg.Print()
+}
+
+func (dg *DeviceGraph) Print() error {
+	if level, err := log.GetPackageLogLevel(); err == nil && level == log.DebugLevel {
+		output := ""
+		routeNumber := 1
+		for k, v := range dg.Routes {
+			key := fmt.Sprintf("LP:%d->LP:%d", k.Ingress, k.Egress)
+			val := ""
+			for _, i := range v {
+				val += fmt.Sprintf("{%d->%s->%d},", i.Ingress, i.DeviceID, i.Egress)
+			}
+			val = val[:len(val)-1]
+			output += fmt.Sprintf("%d:{%s=>%s}   ", routeNumber, key, fmt.Sprintf("[%s]", val))
+			routeNumber += 1
+		}
+		log.Debugw("graph_routes", log.Fields{"lDeviceId": dg.logicalDeviceId, "Routes": output})
+	}
+	return nil
+}
+
+//getDevice returns the device either from the local cache (default) or from the model.
+//TODO: Set a cache timeout such that we do not use invalid data.  The full device lifecycle should also
+//be taken in consideration
+func (dg *DeviceGraph) getDevice(id string) (*voltha.Device, error) {
+	dg.cachedDevicesLock.RLock()
+	if d, exist := dg.cachedDevices[id]; exist {
+		dg.cachedDevicesLock.RUnlock()
+		//log.Debugw("getDevice - returned from cache", log.Fields{"deviceId": id})
+		return d, nil
+	}
+	dg.cachedDevicesLock.RUnlock()
+	//	Not cached
+	if d, err := dg.getDeviceFromModel(id); err != nil {
+		log.Errorw("device-not-found", log.Fields{"deviceId": id, "error": err})
+		return nil, err
+	} else { // cache it
+		dg.cachedDevicesLock.Lock()
+		dg.cachedDevices[id] = d
+		dg.cachedDevicesLock.Unlock()
+		//log.Debugw("getDevice - returned from model", log.Fields{"deviceId": id})
+		return d, nil
+	}
+}
+
+// addDevice adds a device to a device graph and setup edges that represent the device connections to its peers
+func (dg *DeviceGraph) addDevice(device *voltha.Device, g goraph.Graph, devicesAdded *map[string]string, portsAdded *map[string]string,
+	boundaryPorts map[string]uint32) goraph.Graph {
+
+	if device == nil {
+		return g
+	}
+
+	if _, exist := (*devicesAdded)[device.Id]; !exist {
+		g.AddNode(goraph.NewNode(device.Id))
+		(*devicesAdded)[device.Id] = device.Id
+	}
+
+	var portId string
+	var peerPortId string
+	for _, port := range device.Ports {
+		portId = concatDeviceIdPortId(device.Id, port.PortNo)
+		if _, exist := (*portsAdded)[portId]; !exist {
+			(*portsAdded)[portId] = portId
+			g.AddNode(goraph.NewNode(portId))
+			g.AddEdge(goraph.StringID(device.Id), goraph.StringID(portId), 1)
+			g.AddEdge(goraph.StringID(portId), goraph.StringID(device.Id), 1)
+		}
+		for _, peer := range port.Peers {
+			if _, exist := (*devicesAdded)[peer.DeviceId]; !exist {
+				d, _ := dg.getDevice(peer.DeviceId)
+				g = dg.addDevice(d, g, devicesAdded, portsAdded, boundaryPorts)
+			} else {
+				peerPortId = concatDeviceIdPortId(peer.DeviceId, peer.PortNo)
+				g.AddEdge(goraph.StringID(portId), goraph.StringID(peerPortId), 1)
+				g.AddEdge(goraph.StringID(peerPortId), goraph.StringID(portId), 1)
+			}
+		}
+	}
+	return g
+}
+
+//portExist returns true if the port ID is already part of the boundary ports map.
+func (dg *DeviceGraph) portExist(id string) bool {
+	dg.boundaryPortsLock.RLock()
+	defer dg.boundaryPortsLock.RUnlock()
+	_, exist := dg.boundaryPorts[id]
+	return exist
+}
+
+// buildPathsToAllRootPorts builds all the paths from the non-root logical port to all root ports
+// on the logical device
+func (dg *DeviceGraph) buildPathsToAllRootPorts(lp *voltha.LogicalPort) map[OFPortLink][]RouteHop {
+	paths := dg.Routes
+	source := concatDeviceIdPortId(lp.DeviceId, lp.DevicePortNo)
+	sourcePort := lp.OfpPort.PortNo
+	ch := make(chan *ofPortLinkToPath)
+	numBuildRequest := 0
+	for target, targetPort := range dg.rootPortsString {
+		go dg.buildRoute(source, target, sourcePort, targetPort, ch)
+		numBuildRequest += 1
+	}
+	responseReceived := 0
+forloop:
+	for {
+		if responseReceived == numBuildRequest {
+			break
+		}
+		select {
+		case res, ok := <-ch:
+			if !ok {
+				log.Debug("channel closed")
+				break forloop
+			}
+			if res != nil && len(res.path) > 0 {
+				paths[res.link] = res.path
+				paths[OFPortLink{Ingress: res.link.Egress, Egress: res.link.Ingress}] = getReverseRoute(res.path)
+			}
+		}
+		responseReceived += 1
+	}
+	return paths
+}
+
+// buildPathsToAllNonRootPorts builds all the paths from the root logical port to all non-root ports
+// on the logical device
+func (dg *DeviceGraph) buildPathsToAllNonRootPorts(lp *voltha.LogicalPort) map[OFPortLink][]RouteHop {
+	paths := dg.Routes
+	source := concatDeviceIdPortId(lp.DeviceId, lp.DevicePortNo)
+	sourcePort := lp.OfpPort.PortNo
+	ch := make(chan *ofPortLinkToPath)
+	numBuildRequest := 0
+	for target, targetPort := range dg.nonRootPortsString {
+		go dg.buildRoute(source, target, sourcePort, targetPort, ch)
+		numBuildRequest += 1
+	}
+	responseReceived := 0
+forloop:
+	for {
+		if responseReceived == numBuildRequest {
+			break
+		}
+		select {
+		case res, ok := <-ch:
+			if !ok {
+				log.Debug("channel closed")
+				break forloop
+			}
+			if res != nil && len(res.path) > 0 {
+				paths[res.link] = res.path
+				paths[OFPortLink{Ingress: res.link.Egress, Egress: res.link.Ingress}] = getReverseRoute(res.path)
+			}
+		}
+		responseReceived += 1
+	}
+	return paths
+}
+
+//buildRoute builds a route between a source and a target logical port
+func (dg *DeviceGraph) buildRoute(sourceId, targetId string, sourcePort, targetPort uint32, ch chan *ofPortLinkToPath) {
+	var pathIds []goraph.ID
+	path := make([]RouteHop, 0)
+	var err error
+	var hop RouteHop
+	var result *ofPortLinkToPath
+
+	if sourceId == targetId {
+		ch <- result
+		return
+	}
+	//Ignore Root - Root Routes
+	if dg.IsRootPort(sourcePort) && dg.IsRootPort(targetPort) {
+		ch <- result
+		return
+	}
+
+	//Ignore non-Root - non-Root Routes
+	if !dg.IsRootPort(sourcePort) && !dg.IsRootPort(targetPort) {
+		ch <- result
+		return
+	}
+
+	if pathIds, _, err = goraph.Dijkstra(dg.GGraph, goraph.StringID(sourceId), goraph.StringID(targetId)); err != nil {
+		log.Errorw("no-path", log.Fields{"sourceId": sourceId, "targetId": targetId, "error": err})
+		ch <- result
+		return
+	}
+	if len(pathIds)%3 != 0 {
+		ch <- result
+		return
+	}
+	var deviceId string
+	var ingressPort uint32
+	var egressPort uint32
+	for i := 0; i < len(pathIds); i = i + 3 {
+		if deviceId, ingressPort, err = splitIntoDeviceIdPortId(pathIds[i].String()); err != nil {
+			log.Errorw("id-error", log.Fields{"sourceId": sourceId, "targetId": targetId, "error": err})
+			break
+		}
+		if _, egressPort, err = splitIntoDeviceIdPortId(pathIds[i+2].String()); err != nil {
+			log.Errorw("id-error", log.Fields{"sourceId": sourceId, "targetId": targetId, "error": err})
+			break
+		}
+		hop = RouteHop{Ingress: ingressPort, DeviceID: deviceId, Egress: egressPort}
+		path = append(path, hop)
+	}
+	result = &ofPortLinkToPath{link: OFPortLink{Ingress: sourcePort, Egress: targetPort}, path: path}
+	ch <- result
+}
+
+//buildRoutes build all routes between all the ports on the logical device
+func (dg *DeviceGraph) buildRoutes() map[OFPortLink][]RouteHop {
+	paths := make(map[OFPortLink][]RouteHop)
+	ch := make(chan *ofPortLinkToPath)
+	numBuildRequest := 0
+	for source, sourcePort := range dg.boundaryPorts {
+		for target, targetPort := range dg.boundaryPorts {
+			go dg.buildRoute(source, target, sourcePort, targetPort, ch)
+			numBuildRequest += 1
+		}
+	}
+	responseReceived := 0
+forloop:
+	for {
+		if responseReceived == numBuildRequest {
+			break
+		}
+		select {
+		case res, ok := <-ch:
+			if !ok {
+				log.Debug("channel closed")
+				break forloop
+			}
+			if res != nil && len(res.path) > 0 {
+				paths[res.link] = res.path
+			}
+		}
+		responseReceived += 1
+	}
+	return paths
+}
+
+// reset cleans up the device graph
+func (dg *DeviceGraph) reset() {
+	dg.devicesAdded = make(map[string]string)
+	dg.portsAdded = make(map[string]string)
+	dg.rootPortsString = make(map[string]uint32)
+	dg.nonRootPortsString = make(map[string]uint32)
+	dg.RootPorts = make(map[uint32]uint32)
+	dg.boundaryPorts = make(map[string]uint32)
+	dg.Routes = make(map[OFPortLink][]RouteHop)
+	dg.cachedDevices = make(map[string]*voltha.Device)
+}
+
+//concatDeviceIdPortId formats a portid using the device id and the port number
+func concatDeviceIdPortId(deviceId string, portNo uint32) string {
+	return fmt.Sprintf("%s:%d", deviceId, portNo)
+}
+
+// splitIntoDeviceIdPortId extracts the device id and port number from the portId
+func splitIntoDeviceIdPortId(id string) (string, uint32, error) {
+	result := strings.Split(id, ":")
+	if len(result) != 2 {
+		return "", 0, errors.New(fmt.Sprintf("invalid-id-%s", id))
+	}
+	if temp, err := strconv.ParseInt(result[1], 10, 32); err != nil {
+		return "", 0, errors.New(fmt.Sprintf("invalid-id-%s-%s", id, err.Error()))
+	} else {
+		return result[0], uint32(temp), nil
+	}
+}
+
+//getReverseRoute returns the reverse of the route in param
+func getReverseRoute(route []RouteHop) []RouteHop {
+	reverse := make([]RouteHop, len(route))
+	for i, j := 0, len(route)-1; i < j; i, j = i+1, j-1 {
+		reverse[i], reverse[j] = route[j], route[i]
+	}
+	return reverse
+}