diff --git a/db/model/proxy_test.go b/db/model/proxy_test.go
index 45329fd..6226caa 100644
--- a/db/model/proxy_test.go
+++ b/db/model/proxy_test.go
@@ -21,6 +21,7 @@
 	"github.com/google/uuid"
 	"github.com/opencord/voltha-go/common/log"
 	"github.com/opencord/voltha-go/protos/common"
+	"github.com/opencord/voltha-go/protos/openflow_13"
 	"github.com/opencord/voltha-go/protos/voltha"
 	"reflect"
 	"strconv"
@@ -47,8 +48,41 @@
 		DbPort:    2379,
 		DbTimeout: 5,
 	}
+	ports = []*voltha.Port{
+		{
+			PortNo:     123,
+			Label:      "test-port-0",
+			Type:       voltha.Port_PON_OLT,
+			AdminState: common.AdminState_ENABLED,
+			OperStatus: common.OperStatus_ACTIVE,
+			DeviceId:   "etcd_port-0-device-id",
+			Peers:      []*voltha.Port_PeerPort{},
+		},
+	}
+
+	stats = &openflow_13.OfpFlowStats{
+		Id: 1111,
+	}
+	flows = &openflow_13.Flows{
+		Items: []*openflow_13.OfpFlowStats{stats},
+	}
+	device = &voltha.Device{
+		Id:         devId,
+		Type:       "simulated_olt",
+		Address:    &voltha.Device_HostAndPort{HostAndPort: "1.2.3.4:5555"},
+		AdminState: voltha.AdminState_PREPROVISIONED,
+		Flows:      flows,
+		Ports:      ports,
+	}
 	devId          string
 	targetDeviceId string
+
+	preAddExecuted      = false
+	postAddExecuted     = false
+	preUpdateExecuted   = false
+	postUpdateExecuted  = false
+	preRemoveExecuted   = false
+	postRemoveExecuted = false
 )
 
 func init() {
@@ -68,7 +102,60 @@
 	pt.Proxy = pt.Root.GetProxy("/", false)
 }
 
-func Test_Proxy_1_GetDevices(t *testing.T) {
+func commonCallback(args ...interface{}) interface{} {
+	log.Infof("Running common callback - arg count: %s", len(args))
+
+	for i := 0; i < len(args); i++ {
+		log.Infof("ARG %d : %+v", i, args[i])
+	}
+	execStatus := args[1].(*bool)
+
+	// Inform the caller that the callback was executed
+	*execStatus = true
+
+	return nil
+}
+
+func Test_Proxy_1_1_Add_NewDevice(t *testing.T) {
+	devIdBin, _ := uuid.New().MarshalBinary()
+	devId = "0001" + hex.EncodeToString(devIdBin)[:12]
+
+	pt.Proxy.RegisterCallback(PRE_ADD, commonCallback, "PRE_ADD instructions", &preAddExecuted)
+	pt.Proxy.RegisterCallback(POST_ADD, commonCallback, "POST_ADD instructions", &postAddExecuted)
+
+	device.Id = devId
+	if added := pt.Proxy.Add("/devices", device, ""); added == nil {
+		t.Error("Failed to add device")
+	} else {
+		t.Logf("Added device : %+v", added)
+	}
+
+	if d := pt.Proxy.Get("/devices/"+devId, 0, false, ""); !reflect.ValueOf(d).IsValid() {
+		t.Error("Failed to find added device")
+	} else {
+		djson, _ := json.Marshal(d)
+		t.Logf("Found device: %s", string(djson))
+	}
+
+	if !preAddExecuted {
+		t.Error("PRE_ADD callback was not executed")
+	}
+	if !postAddExecuted {
+		t.Error("POST_ADD callback was not executed")
+	}
+}
+
+func Test_Proxy_1_2_Add_ExistingDevice(t *testing.T) {
+	device.Id = devId
+	if added := pt.Proxy.Add("/devices", device, ""); added == nil {
+		t.Logf("Successfully detected that the device already exists: %s", devId)
+	} else {
+		t.Errorf("A new device should not have been created : %+v", added)
+	}
+
+}
+
+func Test_Proxy_2_1_Get_AllDevices(t *testing.T) {
 	devices := pt.Proxy.Get("/devices", 1, false, "")
 
 	if len(devices.([]interface{})) == 0 {
@@ -76,64 +163,132 @@
 	} else {
 		// Save the target device id for later tests
 		targetDeviceId = devices.([]interface{})[0].(*voltha.Device).Id
-		t.Logf("retrieved devices: %+v", devices)
+		t.Logf("retrieved all devices: %+v", devices)
 	}
 }
 
-func Test_Proxy_2_AddDevice(t *testing.T) {
-	devIdBin, _ := uuid.New().MarshalBinary()
-	devId = "0001" + hex.EncodeToString(devIdBin)[:12]
-
-	ports := []*voltha.Port{
-		{
-			PortNo:     123,
-			Label:      "test-port-0",
-			Type:       voltha.Port_PON_OLT,
-			AdminState: common.AdminState_ENABLED,
-			OperStatus: common.OperStatus_ACTIVE,
-			DeviceId:   "etcd_port-0-device-id",
-			Peers:      []*voltha.Port_PeerPort{},
-		},
-	}
-
-	device := &voltha.Device{
-		Id:         devId,
-		Type:       "simulated_olt",
-		Address:    &voltha.Device_HostAndPort{HostAndPort: "1.2.3.4:5555"},
-		AdminState: voltha.AdminState_PREPROVISIONED,
-		Ports:      ports,
-	}
-
-	if added := pt.Proxy.Add("/devices", device, ""); added == nil {
-		t.Error("Failed to add device")
-	} else {
-		t.Logf("Added device : %+v", added)
-	}
-}
-
-func Test_Proxy_3_GetDevice_PostAdd(t *testing.T) {
-	if d := pt.Proxy.Get("/devices/"+devId, 0, false, ""); !reflect.ValueOf(d).IsValid() {
-		t.Error("Failed to find added device")
+func Test_Proxy_2_2_Get_SingleDevice(t *testing.T) {
+	if d := pt.Proxy.Get("/devices/"+targetDeviceId, 0, false, ""); !reflect.ValueOf(d).IsValid() {
+		t.Errorf("Failed to find device : %s", targetDeviceId)
 	} else {
 		djson, _ := json.Marshal(d)
+		t.Logf("Found device: %s", string(djson))
+	}
 
-		t.Logf("Found device: count: %s", djson)
+}
+
+func Test_Proxy_3_1_Update_Device_WithRootProxy(t *testing.T) {
+	if retrieved := pt.Proxy.Get("/devices/"+targetDeviceId, 1, false, ""); retrieved == nil {
+		t.Error("Failed to get device")
+	} else {
+		var fwVersion int
+		if retrieved.(*voltha.Device).FirmwareVersion == "n/a" {
+			fwVersion = 0
+		} else {
+			fwVersion, _ = strconv.Atoi(retrieved.(*voltha.Device).FirmwareVersion)
+			fwVersion += 1
+		}
+
+		preUpdateExecuted = false
+		postUpdateExecuted = false
+
+		pt.Proxy.RegisterCallback(
+			PRE_UPDATE,
+			commonCallback,
+			"PRE_UPDATE instructions (root proxy)", &preUpdateExecuted,
+		)
+		pt.Proxy.RegisterCallback(
+			POST_UPDATE,
+			commonCallback,
+			"POST_UPDATE instructions (root proxy)", &postUpdateExecuted,
+		)
+
+		//cloned := reflect.ValueOf(retrieved).Elem().Interface().(voltha.Device)
+		//cloned.FirmwareVersion = strconv.Itoa(fwVersion)
+		retrieved.(*voltha.Device).FirmwareVersion = strconv.Itoa(fwVersion)
+		//t.Logf("Before update : %+v", cloned)
+
+		if afterUpdate := pt.Proxy.Update("/devices/"+targetDeviceId, retrieved, false, ""); afterUpdate == nil {
+			t.Error("Failed to update device")
+		} else {
+			t.Logf("Updated device : %+v", afterUpdate.(Revision).GetData())
+		}
+		if d := pt.Proxy.Get("/devices/"+targetDeviceId, 0, false, ""); !reflect.ValueOf(d).IsValid() {
+			t.Error("Failed to find updated device (root proxy)")
+		} else {
+			djson, _ := json.Marshal(d)
+			t.Logf("Found device (root proxy): %s", string(djson))
+		}
+
+		if !preUpdateExecuted {
+			t.Error("PRE_UPDATE callback was not executed")
+		}
+		if !postUpdateExecuted {
+			t.Error("POST_UPDATE callback was not executed")
+		}
 	}
 }
-func Test_Proxy_3_1_RegisterProxy(t *testing.T) {
+
+func Test_Proxy_3_2_Update_Flow_WithSubProxy(t *testing.T) {
 	// Get a device proxy and update a specific port
-	devProxy := pt.Root.GetProxy("/devices/"+devId, false)
-	port123 := devProxy.Get("/ports/123", 0, false, "")
-	t.Logf("got ports: %+v", port123)
+	devflowsProxy := pt.Root.GetProxy("/devices/"+devId+"/flows", false)
+	flows := devflowsProxy.Get("/", 0, false, "")
+	//flows.([]interface{})[0].(*openflow_13.Flows).Items[0].TableId = 2222
+	flows.([]interface{})[0].(*openflow_13.Flows).Items[0].TableId = 2244
+	//flows.(*openflow_13.Flows).Items[0].TableId = 2244
+	t.Logf("before updated flows: %+v", flows)
 
-	devProxy.RegisterCallback(POST_UPDATE, deviceCallback, nil)
+	//devPortsProxy := pt.Root.node.GetProxy("/devices/"+devId+"/ports", false)
+	//port123 := devPortsProxy.Get("/123", 0, false, "")
+	//t.Logf("got ports: %+v", port123)
+	//port123.(*voltha.Port).OperStatus = common.OperStatus_DISCOVERED
 
-	port123.(*voltha.Port).OperStatus = common.OperStatus_DISCOVERED
+	preUpdateExecuted = false
+	postUpdateExecuted = false
 
-	devProxy.Update("/ports/123", port123, false, "")
-	updated := devProxy.Get("/ports", 0, false, "")
-	t.Logf("got updated ports: %+v", updated)
+	devflowsProxy.RegisterCallback(
+		PRE_UPDATE,
+		commonCallback,
+		"PRE_UPDATE instructions (flows proxy)", &preUpdateExecuted,
+	)
+	devflowsProxy.RegisterCallback(
+		POST_UPDATE,
+		commonCallback,
+		"POST_UPDATE instructions (flows proxy)", &postUpdateExecuted,
+	)
 
+	kvFlows := devflowsProxy.Get("/", 0, false, "")
+
+	if reflect.DeepEqual(flows, kvFlows) {
+		t.Errorf("Local changes have changed the KV store contents -  local:%+v, kv: %+v", flows, kvFlows)
+	}
+
+	if updated := devflowsProxy.Update("/", flows.([]interface{})[0], false, ""); updated == nil {
+		t.Error("Failed to update flow")
+	} else {
+		t.Logf("Updated flows : %+v", updated)
+	}
+
+	if d := devflowsProxy.Get("/", 0, false, ""); d == nil {
+		t.Error("Failed to find updated flows (flows proxy)")
+	} else {
+		djson, _ := json.Marshal(d)
+		t.Logf("Found flows (flows proxy): %s", string(djson))
+	}
+
+	if d := pt.Proxy.Get("/devices/"+devId+"/flows", 0, false, ""); !reflect.ValueOf(d).IsValid() {
+		t.Error("Failed to find updated flows (root proxy)")
+	} else {
+		djson, _ := json.Marshal(d)
+		t.Logf("Found flows (root proxy): %s", string(djson))
+	}
+
+	if !preUpdateExecuted {
+		t.Error("PRE_UPDATE callback was not executed")
+	}
+	if !postUpdateExecuted {
+		t.Error("POST_UPDATE callback was not executed")
+	}
 	//
 	// Get a device proxy and update all its ports
 	//
@@ -141,7 +296,7 @@
 	//devProxy := pt.Root.GetProxy("/devices/"+devId, false)
 	//ports := devProxy.Get("/ports", 0, false, "")
 	//t.Logf("got ports: %+v", ports)
-	//devProxy.RegisterCallback(POST_UPDATE, deviceCallback, nil)
+	//devProxy.RegisterCallback(POST_UPDATE, commonCallback, nil)
 	//
 	//ports.([]interface{})[0].(*voltha.Port).OperStatus = common.OperStatus_DISCOVERED
 	//
@@ -156,7 +311,7 @@
 	//devProxy := pt.Root.GetProxy("/devices/"+devId, false)
 	//ports := devProxy.Get("/ports", 0, false, "")
 	//t.Logf("got ports: %+v", ports)
-	//devProxy.RegisterCallback(POST_UPDATE, deviceCallback, nil)
+	//devProxy.RegisterCallback(POST_UPDATE, commonCallback, nil)
 	//
 	//ports.([]interface{})[0].(*voltha.Port).OperStatus = common.OperStatus_DISCOVERED
 	//
@@ -165,61 +320,39 @@
 	//t.Logf("got updated ports: %+v", updated)
 }
 
-func Test_Proxy_3_2_GetDevice_PostRegister(t *testing.T) {
-	if d := pt.Proxy.Get("/devices/"+devId, 0, false, ""); !reflect.ValueOf(d).IsValid() {
-		t.Error("Failed to find updated registered device")
-	} else {
-		djson, _ := json.Marshal(d)
+func Test_Proxy_4_1_Remove_Device(t *testing.T) {
+	preRemoveExecuted = false
+	postRemoveExecuted = false
 
-		t.Logf("Found device: count: %s", djson)
-	}
-}
+	pt.Proxy.RegisterCallback(
+		PRE_REMOVE,
+		commonCallback,
+		"PRE_REMOVE instructions (root proxy)", &preRemoveExecuted,
+	)
+	pt.Proxy.RegisterCallback(
+		POST_REMOVE,
+		commonCallback,
+		"POST_REMOVE instructions (root proxy)", &postRemoveExecuted,
+	)
 
-func Test_Proxy_4_UpdateDevice(t *testing.T) {
-	if retrieved := pt.Proxy.Get("/devices/"+targetDeviceId, 1, false, ""); retrieved == nil {
-		t.Error("Failed to get device")
-	} else {
-		var fwVersion int
-		if retrieved.(*voltha.Device).FirmwareVersion == "n/a" {
-			fwVersion = 0
-		} else {
-			fwVersion, _ = strconv.Atoi(retrieved.(*voltha.Device).FirmwareVersion)
-			fwVersion += 1
-		}
-
-		cloned := reflect.ValueOf(retrieved).Elem().Interface().(voltha.Device)
-		cloned.FirmwareVersion = strconv.Itoa(fwVersion)
-		t.Logf("Before update : %+v", cloned)
-
-		if afterUpdate := pt.Proxy.Update("/devices/"+targetDeviceId, &cloned, false, ""); afterUpdate == nil {
-			t.Error("Failed to update device")
-		} else {
-			t.Logf("Updated device : %+v", afterUpdate.(Revision).GetData())
-		}
-	}
-}
-
-func Test_Proxy_5_GetDevice_PostUpdate(t *testing.T) {
-	device := pt.Proxy.Get("/devices/"+targetDeviceId, 0, false, "")
-
-	t.Logf("content of updated device: %+v", device)
-}
-
-func Test_Proxy_6_RemoveDevice(t *testing.T) {
 	if removed := pt.Proxy.Remove("/devices/"+devId, ""); removed == nil {
 		t.Error("Failed to remove device")
 	} else {
 		t.Logf("Removed device : %+v", removed)
 	}
-}
-
-func Test_Proxy_7_GetDevice_PostRemove(t *testing.T) {
 	if d := pt.Proxy.Get("/devices/"+devId, 0, false, ""); reflect.ValueOf(d).IsValid() {
 		djson, _ := json.Marshal(d)
 		t.Errorf("Device was not removed - %s", djson)
 	} else {
 		t.Logf("Device was removed: %s", devId)
 	}
+
+	if !preRemoveExecuted {
+		t.Error("PRE_UPDATE callback was not executed")
+	}
+	if !postRemoveExecuted {
+		t.Error("POST_UPDATE callback was not executed")
+	}
 }
 
 // -----------------------------
@@ -232,10 +365,6 @@
 	log.Infof("Running first callback - name: %s, id: %s\n", name, id)
 	return nil
 }
-func deviceCallback(args ...interface{}) interface{} {
-	log.Infof("Running device callback\n")
-	return nil
-}
 func secondCallback(args ...interface{}) interface{} {
 	name := args[0].(map[string]string)
 	id := args[1]
@@ -263,10 +392,11 @@
 }
 
 func Test_Proxy_Callbacks_2_Invoke_WithNoInterruption(t *testing.T) {
-	pt.Proxy.InvokeCallbacks(PRE_ADD, nil, true)
+	pt.Proxy.InvokeCallbacks(PRE_ADD, false, nil)
 }
+
 func Test_Proxy_Callbacks_3_Invoke_WithInterruption(t *testing.T) {
-	pt.Proxy.InvokeCallbacks(PRE_ADD, nil, false)
+	pt.Proxy.InvokeCallbacks(PRE_ADD, true, nil)
 }
 
 func Test_Proxy_Callbacks_4_Unregister(t *testing.T) {
@@ -274,3 +404,11 @@
 	pt.Proxy.UnregisterCallback(PRE_ADD, secondCallback)
 	pt.Proxy.UnregisterCallback(PRE_ADD, thirdCallback)
 }
+
+//func Test_Proxy_Callbacks_5_Add(t *testing.T) {
+//	pt.Proxy.Root.AddCallback(pt.Proxy.InvokeCallbacks, POST_UPDATE, false, "some data", "some new data")
+//}
+//
+//func Test_Proxy_Callbacks_6_Execute(t *testing.T) {
+//	pt.Proxy.Root.ExecuteCallbacks()
+//}