rw_core/graph/device_graph.go - voltha-go - Gitiles

 /*
  * 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-lib-go/pkg/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, false)
 		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) {
 	log.Debugw("Addport", log.Fields{"logicalPort": lp})
 	//  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) {
 		return
 	}
 	// Add the port to the set of boundary ports
 	dg.boundaryPorts[portId] = lp.OfpPort.PortNo

 	// 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, false)
 	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 {
 	log.Debugw("Print", log.Fields{"graph": dg.logicalDeviceId, "boundaryPorts": dg.boundaryPorts})
 	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
 		}
 		if len(dg.Routes) == 0 {
 			log.Debugw("no-routes-found", log.Fields{"lDeviceId": dg.logicalDeviceId, "Graph": dg.GGraph.String()})
 		} else {
 			log.Debugw("graph_routes", log.Fields{"lDeviceId": dg.logicalDeviceId, "Routes": output})
 		}
 	}
 	return nil
 }

 func (dg *DeviceGraph) IsUpToDate(ld *voltha.LogicalDevice) bool {
 	if ld != nil {
 		if len(dg.boundaryPorts) != len(ld.Ports) {
 			return false
 		}
 		var portId string
 		var val uint32
 		var exist bool
 		for _, lp := range ld.Ports {
 			portId = concatDeviceIdPortId(lp.DeviceId, lp.DevicePortNo)
 			if val, exist = dg.boundaryPorts[portId]; !exist || val != lp.OfpPort.PortNo {
 				return false
 			}
 		}
 		return true
 	}
 	return len(dg.boundaryPorts) == 0
 }

 //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, useCache bool) (*voltha.Device, error) {
 	if useCache {
 		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
 	}

 	log.Debugw("Adding-device", log.Fields{"deviceId": device.Id, "ports": device.Ports})

 	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, true)
 				g = dg.addDevice(d, g, devicesAdded, portsAdded, boundaryPorts)
 			}
 			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
 func getReverseRoute(route []RouteHop) []RouteHop {
 	reverse := make([]RouteHop, len(route))
 	for i, j := 0, len(route)-1; j >= 0; i, j = i+1, j-1 {
 		reverse[i].DeviceID, reverse[i].Ingress, reverse[i].Egress = route[j].DeviceID, route[j].Egress, route[j].Ingress
 	}
 	return reverse
 }
	/*
	* 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-lib-go/pkg/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, false)
	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) {
	log.Debugw("Addport", log.Fields{"logicalPort": lp})
	// 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) {
	return
	}
	// Add the port to the set of boundary ports
	dg.boundaryPorts[portId] = lp.OfpPort.PortNo

	// 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, false)
	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 {
	log.Debugw("Print", log.Fields{"graph": dg.logicalDeviceId, "boundaryPorts": dg.boundaryPorts})
	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
	}
	if len(dg.Routes) == 0 {
	log.Debugw("no-routes-found", log.Fields{"lDeviceId": dg.logicalDeviceId, "Graph": dg.GGraph.String()})
	} else {
	log.Debugw("graph_routes", log.Fields{"lDeviceId": dg.logicalDeviceId, "Routes": output})
	}
	}
	return nil
	}

	func (dg DeviceGraph) IsUpToDate(ld voltha.LogicalDevice) bool {
	if ld != nil {
	if len(dg.boundaryPorts) != len(ld.Ports) {
	return false
	}
	var portId string
	var val uint32
	var exist bool
	for _, lp := range ld.Ports {
	portId = concatDeviceIdPortId(lp.DeviceId, lp.DevicePortNo)
	if val, exist = dg.boundaryPorts[portId]; !exist \|\| val != lp.OfpPort.PortNo {
	return false
	}
	}
	return true
	}
	return len(dg.boundaryPorts) == 0
	}

	//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, useCache bool) (voltha.Device, error) {
	if useCache {
	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
	}

	log.Debugw("Adding-device", log.Fields{"deviceId": device.Id, "ports": device.Ports})

	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, true)
	g = dg.addDevice(d, g, devicesAdded, portsAdded, boundaryPorts)
	}
	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
	func getReverseRoute(route []RouteHop) []RouteHop {
	reverse := make([]RouteHop, len(route))
	for i, j := 0, len(route)-1; j >= 0; i, j = i+1, j-1 {
	reverse[i].DeviceID, reverse[i].Ingress, reverse[i].Egress = route[j].DeviceID, route[j].Egress, route[j].Ingress
	}
	return reverse
	}