diff --git a/vendor/github.com/opencord/voltha-lib-go/v4/pkg/db/backend.go b/vendor/github.com/opencord/voltha-lib-go/v4/pkg/db/backend.go
new file mode 100644
index 0000000..d6867a5
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-lib-go/v4/pkg/db/backend.go
@@ -0,0 +1,262 @@
+/*
+ * 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 db
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/opencord/voltha-lib-go/v4/pkg/db/kvstore"
+	"github.com/opencord/voltha-lib-go/v4/pkg/log"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+const (
+	// Default Minimal Interval for posting alive state of backend kvstore on Liveness Channel
+	DefaultLivenessChannelInterval = time.Second * 30
+)
+
+// Backend structure holds details for accessing the kv store
+type Backend struct {
+	Client                  kvstore.Client
+	StoreType               string
+	Timeout                 time.Duration
+	Address                 string
+	PathPrefix              string
+	alive                   bool // Is this backend connection alive?
+	livenessMutex           sync.Mutex
+	liveness                chan bool     // channel to post alive state
+	LivenessChannelInterval time.Duration // regularly push alive state beyond this interval
+	lastLivenessTime        time.Time     // Instant of last alive state push
+}
+
+// NewBackend creates a new instance of a Backend structure
+func NewBackend(ctx context.Context, storeType string, address string, timeout time.Duration, pathPrefix string) *Backend {
+	var err error
+
+	b := &Backend{
+		StoreType:               storeType,
+		Address:                 address,
+		Timeout:                 timeout,
+		LivenessChannelInterval: DefaultLivenessChannelInterval,
+		PathPrefix:              pathPrefix,
+		alive:                   false, // connection considered down at start
+	}
+
+	if b.Client, err = b.newClient(ctx, address, timeout); err != nil {
+		logger.Errorw(ctx, "failed-to-create-kv-client",
+			log.Fields{
+				"type": storeType, "address": address,
+				"timeout": timeout, "prefix": pathPrefix,
+				"error": err.Error(),
+			})
+	}
+
+	return b
+}
+
+func (b *Backend) newClient(ctx context.Context, address string, timeout time.Duration) (kvstore.Client, error) {
+	switch b.StoreType {
+	case "consul":
+		return kvstore.NewConsulClient(ctx, address, timeout)
+	case "etcd":
+		return kvstore.NewEtcdClient(ctx, address, timeout, log.WarnLevel)
+	}
+	return nil, errors.New("unsupported-kv-store")
+}
+
+func (b *Backend) makePath(ctx context.Context, key string) string {
+	path := fmt.Sprintf("%s/%s", b.PathPrefix, key)
+	return path
+}
+
+func (b *Backend) updateLiveness(ctx context.Context, alive bool) {
+	// Periodically push stream of liveness data to the channel,
+	// so that in a live state, the core does not timeout and
+	// send a forced liveness message. Push alive state if the
+	// last push to channel was beyond livenessChannelInterval
+	b.livenessMutex.Lock()
+	defer b.livenessMutex.Unlock()
+	if b.liveness != nil {
+		if b.alive != alive {
+			logger.Debug(ctx, "update-liveness-channel-reason-change")
+			b.liveness <- alive
+			b.lastLivenessTime = time.Now()
+		} else if time.Since(b.lastLivenessTime) > b.LivenessChannelInterval {
+			logger.Debug(ctx, "update-liveness-channel-reason-interval")
+			b.liveness <- alive
+			b.lastLivenessTime = time.Now()
+		}
+	}
+
+	// Emit log message only for alive state change
+	if b.alive != alive {
+		logger.Debugw(ctx, "change-kvstore-alive-status", log.Fields{"alive": alive})
+		b.alive = alive
+	}
+}
+
+// Perform a dummy Key Lookup on kvstore to test Connection Liveness and
+// post on Liveness channel
+func (b *Backend) PerformLivenessCheck(ctx context.Context) bool {
+	alive := b.Client.IsConnectionUp(ctx)
+	logger.Debugw(ctx, "kvstore-liveness-check-result", log.Fields{"alive": alive})
+
+	b.updateLiveness(ctx, alive)
+	return alive
+}
+
+// Enable the liveness monitor channel. This channel will report
+// a "true" or "false" on every kvstore operation which indicates whether
+// or not the connection is still Live. This channel is then picked up
+// by the service (i.e. rw_core / ro_core) to update readiness status
+// and/or take other actions.
+func (b *Backend) EnableLivenessChannel(ctx context.Context) chan bool {
+	logger.Debug(ctx, "enable-kvstore-liveness-channel")
+	b.livenessMutex.Lock()
+	defer b.livenessMutex.Unlock()
+	if b.liveness == nil {
+		b.liveness = make(chan bool, 10)
+		b.liveness <- b.alive
+		b.lastLivenessTime = time.Now()
+	}
+
+	return b.liveness
+}
+
+// Extract Alive status of Kvstore based on type of error
+func (b *Backend) isErrorIndicatingAliveKvstore(ctx context.Context, err error) bool {
+	// Alive unless observed an error indicating so
+	alive := true
+
+	if err != nil {
+
+		// timeout indicates kvstore not reachable/alive
+		if err == context.DeadlineExceeded {
+			alive = false
+		}
+
+		// Need to analyze client-specific errors based on backend type
+		if b.StoreType == "etcd" {
+
+			// For etcd backend, consider not-alive only for errors indicating
+			// timedout request or unavailable/corrupted cluster. For all remaining
+			// error codes listed in https://godoc.org/google.golang.org/grpc/codes#Code,
+			// we would not infer a not-alive backend because such a error may also
+			// occur due to bad client requests or sequence of operations
+			switch status.Code(err) {
+			case codes.DeadlineExceeded:
+				fallthrough
+			case codes.Unavailable:
+				fallthrough
+			case codes.DataLoss:
+				alive = false
+			}
+
+			//} else {
+			// TODO: Implement for consul backend; would it be needed ever?
+		}
+	}
+
+	return alive
+}
+
+// List retrieves one or more items that match the specified key
+func (b *Backend) List(ctx context.Context, key string) (map[string]*kvstore.KVPair, error) {
+	span, ctx := log.CreateChildSpan(ctx, "etcd-list")
+	defer span.Finish()
+
+	formattedPath := b.makePath(ctx, key)
+	logger.Debugw(ctx, "listing-key", log.Fields{"key": key, "path": formattedPath})
+
+	pair, err := b.Client.List(ctx, formattedPath)
+
+	b.updateLiveness(ctx, b.isErrorIndicatingAliveKvstore(ctx, err))
+
+	return pair, err
+}
+
+// Get retrieves an item that matches the specified key
+func (b *Backend) Get(ctx context.Context, key string) (*kvstore.KVPair, error) {
+	span, ctx := log.CreateChildSpan(ctx, "etcd-get")
+	defer span.Finish()
+
+	formattedPath := b.makePath(ctx, key)
+	logger.Debugw(ctx, "getting-key", log.Fields{"key": key, "path": formattedPath})
+
+	pair, err := b.Client.Get(ctx, formattedPath)
+
+	b.updateLiveness(ctx, b.isErrorIndicatingAliveKvstore(ctx, err))
+
+	return pair, err
+}
+
+// Put stores an item value under the specifed key
+func (b *Backend) Put(ctx context.Context, key string, value interface{}) error {
+	span, ctx := log.CreateChildSpan(ctx, "etcd-put")
+	defer span.Finish()
+
+	formattedPath := b.makePath(ctx, key)
+	logger.Debugw(ctx, "putting-key", log.Fields{"key": key, "path": formattedPath})
+
+	err := b.Client.Put(ctx, formattedPath, value)
+
+	b.updateLiveness(ctx, b.isErrorIndicatingAliveKvstore(ctx, err))
+
+	return err
+}
+
+// Delete removes an item under the specified key
+func (b *Backend) Delete(ctx context.Context, key string) error {
+	span, ctx := log.CreateChildSpan(ctx, "etcd-delete")
+	defer span.Finish()
+
+	formattedPath := b.makePath(ctx, key)
+	logger.Debugw(ctx, "deleting-key", log.Fields{"key": key, "path": formattedPath})
+
+	err := b.Client.Delete(ctx, formattedPath)
+
+	b.updateLiveness(ctx, b.isErrorIndicatingAliveKvstore(ctx, err))
+
+	return err
+}
+
+// CreateWatch starts watching events for the specified key
+func (b *Backend) CreateWatch(ctx context.Context, key string, withPrefix bool) chan *kvstore.Event {
+	span, ctx := log.CreateChildSpan(ctx, "etcd-create-watch")
+	defer span.Finish()
+
+	formattedPath := b.makePath(ctx, key)
+	logger.Debugw(ctx, "creating-key-watch", log.Fields{"key": key, "path": formattedPath})
+
+	return b.Client.Watch(ctx, formattedPath, withPrefix)
+}
+
+// DeleteWatch stops watching events for the specified key
+func (b *Backend) DeleteWatch(ctx context.Context, key string, ch chan *kvstore.Event) {
+	span, ctx := log.CreateChildSpan(ctx, "etcd-delete-watch")
+	defer span.Finish()
+
+	formattedPath := b.makePath(ctx, key)
+	logger.Debugw(ctx, "deleting-key-watch", log.Fields{"key": key, "path": formattedPath})
+
+	b.Client.CloseWatch(ctx, formattedPath, ch)
+}