diff --git a/vendor/github.com/opencord/voltha-go/rw_core/utils/core_utils.go b/vendor/github.com/opencord/voltha-go/rw_core/utils/core_utils.go
new file mode 100644
index 0000000..1e1ed9f
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-go/rw_core/utils/core_utils.go
@@ -0,0 +1,24 @@
+/*
+ * 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 utils
+
+type DeviceID struct {
+	Id string
+}
+
+type LogicalDeviceID struct {
+	Id string
+}
diff --git a/vendor/github.com/opencord/voltha-go/rw_core/utils/flow_utils.go b/vendor/github.com/opencord/voltha-go/rw_core/utils/flow_utils.go
new file mode 100644
index 0000000..10be81a
--- /dev/null
+++ b/vendor/github.com/opencord/voltha-go/rw_core/utils/flow_utils.go
@@ -0,0 +1,377 @@
+/*
+ * 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 utils
+
+import (
+	"bytes"
+	"github.com/cevaris/ordered_map"
+	"github.com/gogo/protobuf/proto"
+	ofp "github.com/opencord/voltha-protos/go/openflow_13"
+	"strings"
+)
+
+type OfpFlowModArgs map[string]uint64
+
+type FlowArgs struct {
+	MatchFields []*ofp.OfpOxmOfbField
+	Actions     []*ofp.OfpAction
+	Command     *ofp.OfpFlowModCommand
+	Priority    uint32
+	KV          OfpFlowModArgs
+}
+
+type GroupArgs struct {
+	GroupId uint32
+	Buckets []*ofp.OfpBucket
+	Command *ofp.OfpGroupModCommand
+}
+
+type FlowsAndGroups struct {
+	Flows  *ordered_map.OrderedMap
+	Groups *ordered_map.OrderedMap
+}
+
+func NewFlowsAndGroups() *FlowsAndGroups {
+	var fg FlowsAndGroups
+	fg.Flows = ordered_map.NewOrderedMap()
+	fg.Groups = ordered_map.NewOrderedMap()
+	return &fg
+}
+
+func (fg *FlowsAndGroups) Copy() *FlowsAndGroups {
+	copyFG := NewFlowsAndGroups()
+	iter := fg.Flows.IterFunc()
+	for kv, ok := iter(); ok; kv, ok = iter() {
+		if protoMsg, isMsg := kv.Value.(*ofp.OfpFlowStats); isMsg {
+			copyFG.Flows.Set(kv.Key, proto.Clone(protoMsg))
+		}
+	}
+	iter = fg.Groups.IterFunc()
+	for kv, ok := iter(); ok; kv, ok = iter() {
+		if protoMsg, isMsg := kv.Value.(*ofp.OfpGroupEntry); isMsg {
+			copyFG.Groups.Set(kv.Key, proto.Clone(protoMsg))
+		}
+	}
+	return copyFG
+}
+
+func (fg *FlowsAndGroups) GetFlow(index int) *ofp.OfpFlowStats {
+	iter := fg.Flows.IterFunc()
+	pos := 0
+	for kv, ok := iter(); ok; kv, ok = iter() {
+		if pos == index {
+			if protoMsg, isMsg := kv.Value.(*ofp.OfpFlowStats); isMsg {
+				return protoMsg
+			}
+			return nil
+		}
+		pos += 1
+	}
+	return nil
+}
+
+func (fg *FlowsAndGroups) ListFlows() []*ofp.OfpFlowStats {
+	flows := make([]*ofp.OfpFlowStats, 0)
+	iter := fg.Flows.IterFunc()
+	for kv, ok := iter(); ok; kv, ok = iter() {
+		if protoMsg, isMsg := kv.Value.(*ofp.OfpFlowStats); isMsg {
+			flows = append(flows, protoMsg)
+		}
+	}
+	return flows
+}
+
+func (fg *FlowsAndGroups) ListGroups() []*ofp.OfpGroupEntry {
+	groups := make([]*ofp.OfpGroupEntry, 0)
+	iter := fg.Groups.IterFunc()
+	for kv, ok := iter(); ok; kv, ok = iter() {
+		if protoMsg, isMsg := kv.Value.(*ofp.OfpGroupEntry); isMsg {
+			groups = append(groups, protoMsg)
+		}
+	}
+	return groups
+}
+
+func (fg *FlowsAndGroups) String() string {
+	var buffer bytes.Buffer
+	iter := fg.Flows.IterFunc()
+	for kv, ok := iter(); ok; kv, ok = iter() {
+		if protoMsg, isMsg := kv.Value.(*ofp.OfpFlowStats); isMsg {
+			buffer.WriteString("\nFlow:\n")
+			buffer.WriteString(proto.MarshalTextString(protoMsg))
+			buffer.WriteString("\n")
+		}
+	}
+	iter = fg.Groups.IterFunc()
+	for kv, ok := iter(); ok; kv, ok = iter() {
+		if protoMsg, isMsg := kv.Value.(*ofp.OfpGroupEntry); isMsg {
+			buffer.WriteString("\nGroup:\n")
+			buffer.WriteString(proto.MarshalTextString(protoMsg))
+			buffer.WriteString("\n")
+		}
+	}
+	return buffer.String()
+}
+
+func (fg *FlowsAndGroups) AddFlow(flow *ofp.OfpFlowStats) {
+	if fg.Flows == nil {
+		fg.Flows = ordered_map.NewOrderedMap()
+	}
+	if fg.Groups == nil {
+		fg.Groups = ordered_map.NewOrderedMap()
+	}
+	//Add flow only if absent
+	if _, exist := fg.Flows.Get(flow.Id); !exist {
+		fg.Flows.Set(flow.Id, flow)
+	}
+}
+
+//AddFrom add flows and groups from the argument into this structure only if they do not already exist
+func (fg *FlowsAndGroups) AddFrom(from *FlowsAndGroups) {
+	iter := from.Flows.IterFunc()
+	for kv, ok := iter(); ok; kv, ok = iter() {
+		if protoMsg, isMsg := kv.Value.(*ofp.OfpFlowStats); isMsg {
+			if _, exist := fg.Flows.Get(protoMsg.Id); !exist {
+				fg.Flows.Set(protoMsg.Id, protoMsg)
+			}
+		}
+	}
+	iter = from.Groups.IterFunc()
+	for kv, ok := iter(); ok; kv, ok = iter() {
+		if protoMsg, isMsg := kv.Value.(*ofp.OfpGroupEntry); isMsg {
+			if _, exist := fg.Groups.Get(protoMsg.Stats.GroupId); !exist {
+				fg.Groups.Set(protoMsg.Stats.GroupId, protoMsg)
+			}
+		}
+	}
+}
+
+type DeviceRules struct {
+	Rules map[string]*FlowsAndGroups
+}
+
+func NewDeviceRules() *DeviceRules {
+	var dr DeviceRules
+	dr.Rules = make(map[string]*FlowsAndGroups)
+	return &dr
+}
+
+func (dr *DeviceRules) Copy() *DeviceRules {
+	copyDR := NewDeviceRules()
+	for key, val := range dr.Rules {
+		copyDR.Rules[key] = val.Copy()
+	}
+	return copyDR
+}
+
+func (dr *DeviceRules) ClearFlows(deviceId string) {
+	if _, exist := dr.Rules[deviceId]; exist {
+		dr.Rules[deviceId].Flows = ordered_map.NewOrderedMap()
+	}
+}
+
+func (dr *DeviceRules) AddFlow(deviceId string, flow *ofp.OfpFlowStats) {
+	if _, exist := dr.Rules[deviceId]; !exist {
+		dr.Rules[deviceId] = NewFlowsAndGroups()
+	}
+	dr.Rules[deviceId].AddFlow(flow)
+}
+
+func (dr *DeviceRules) GetRules() map[string]*FlowsAndGroups {
+	return dr.Rules
+}
+
+func (dr *DeviceRules) String() string {
+	var buffer bytes.Buffer
+	for key, value := range dr.Rules {
+		buffer.WriteString("DeviceId:")
+		buffer.WriteString(key)
+		buffer.WriteString(value.String())
+		buffer.WriteString("\n\n")
+	}
+	return buffer.String()
+}
+
+func (dr *DeviceRules) AddFlowsAndGroup(deviceId string, fg *FlowsAndGroups) {
+	if _, ok := dr.Rules[deviceId]; !ok {
+		dr.Rules[deviceId] = NewFlowsAndGroups()
+	}
+	dr.Rules[deviceId] = fg
+}
+
+// CreateEntryIfNotExist creates a new deviceId in the Map if it does not exist and assigns an
+// empty FlowsAndGroups to it.  Otherwise, it does nothing.
+func (dr *DeviceRules) CreateEntryIfNotExist(deviceId string) {
+	if _, ok := dr.Rules[deviceId]; !ok {
+		dr.Rules[deviceId] = NewFlowsAndGroups()
+	}
+}
+
+/*
+ *  Common flow routines
+ */
+
+//FindOverlappingFlows return a list of overlapping flow(s) where mod is the flow request
+func FindOverlappingFlows(flows []*ofp.OfpFlowStats, mod *ofp.OfpFlowMod) []*ofp.OfpFlowStats {
+	return nil //TODO - complete implementation
+}
+
+// FindFlowById returns the index of the flow in the flows array if present. Otherwise, it returns -1
+func FindFlowById(flows []*ofp.OfpFlowStats, flow *ofp.OfpFlowStats) int {
+	for idx, f := range flows {
+		if flow.Id == f.Id {
+			return idx
+		}
+	}
+	return -1
+}
+
+// FindFlows returns the index in flows where flow if present.  Otherwise, it returns -1
+func FindFlows(flows []*ofp.OfpFlowStats, flow *ofp.OfpFlowStats) int {
+	for idx, f := range flows {
+		if FlowMatch(f, flow) {
+			return idx
+		}
+	}
+	return -1
+}
+
+//FlowMatch returns true if two flows matches on the following flow attributes:
+//TableId, Priority, Flags, Cookie, Match
+func FlowMatch(f1 *ofp.OfpFlowStats, f2 *ofp.OfpFlowStats) bool {
+	keysMatter := []string{"TableId", "Priority", "Flags", "Cookie", "Match"}
+	for _, key := range keysMatter {
+		switch key {
+		case "TableId":
+			if f1.TableId != f2.TableId {
+				return false
+			}
+		case "Priority":
+			if f1.Priority != f2.Priority {
+				return false
+			}
+		case "Flags":
+			if f1.Flags != f2.Flags {
+				return false
+			}
+		case "Cookie":
+			if f1.Cookie != f2.Cookie {
+				return false
+			}
+		case "Match":
+			if strings.Compare(f1.Match.String(), f2.Match.String()) != 0 {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+//FlowMatchesMod returns True if given flow is "covered" by the wildcard flow_mod, taking into consideration of
+//both exact matches as well as masks-based match fields if any. Otherwise return False
+func FlowMatchesMod(flow *ofp.OfpFlowStats, mod *ofp.OfpFlowMod) bool {
+	//Check if flow.cookie is covered by mod.cookie and mod.cookie_mask
+	if (flow.Cookie & mod.CookieMask) != (mod.Cookie & mod.CookieMask) {
+		return false
+	}
+
+	//Check if flow.table_id is covered by flow_mod.table_id
+	if mod.TableId != uint32(ofp.OfpTable_OFPTT_ALL) && flow.TableId != mod.TableId {
+		return false
+	}
+
+	//Check out_port
+	if (mod.OutPort&0x7fffffff) != uint32(ofp.OfpPortNo_OFPP_ANY) && !FlowHasOutPort(flow, mod.OutPort) {
+		return false
+	}
+
+	//	Check out_group
+	if (mod.OutGroup&0x7fffffff) != uint32(ofp.OfpGroup_OFPG_ANY) && !FlowHasOutGroup(flow, mod.OutGroup) {
+		return false
+	}
+
+	//Priority is ignored
+
+	//Check match condition
+	//If the flow_mod match field is empty, that is a special case and indicates the flow entry matches
+	if (mod.Match == nil) || (mod.Match.OxmFields == nil) {
+		//If we got this far and the match is empty in the flow spec, than the flow matches
+		return true
+	} // TODO : implement the flow match analysis
+	return false
+
+}
+
+//FlowHasOutPort returns True if flow has a output command with the given out_port
+func FlowHasOutPort(flow *ofp.OfpFlowStats, outPort uint32) bool {
+	for _, instruction := range flow.Instructions {
+		if instruction.Type == uint32(ofp.OfpInstructionType_OFPIT_APPLY_ACTIONS) {
+			if instruction.GetActions() == nil {
+				return false
+			}
+			for _, action := range instruction.GetActions().Actions {
+				if action.Type == ofp.OfpActionType_OFPAT_OUTPUT {
+					if (action.GetOutput() != nil) && (action.GetOutput().Port == outPort) {
+						return true
+					}
+				}
+
+			}
+		}
+	}
+	return false
+}
+
+//FlowHasOutGroup return True if flow has a output command with the given out_group
+func FlowHasOutGroup(flow *ofp.OfpFlowStats, groupID uint32) bool {
+	for _, instruction := range flow.Instructions {
+		if instruction.Type == uint32(ofp.OfpInstructionType_OFPIT_APPLY_ACTIONS) {
+			if instruction.GetActions() == nil {
+				return false
+			}
+			for _, action := range instruction.GetActions().Actions {
+				if action.Type == ofp.OfpActionType_OFPAT_GROUP {
+					if (action.GetGroup() != nil) && (action.GetGroup().GroupId == groupID) {
+						return true
+					}
+				}
+
+			}
+		}
+	}
+	return false
+}
+
+//FindGroup returns index of group if found, else returns -1
+func FindGroup(groups []*ofp.OfpGroupEntry, groupId uint32) int {
+	for idx, group := range groups {
+		if group.Desc.GroupId == groupId {
+			return idx
+		}
+	}
+	return -1
+}
+
+func FlowsDeleteByGroupId(flows []*ofp.OfpFlowStats, groupId uint32) (bool, []*ofp.OfpFlowStats) {
+	toKeep := make([]*ofp.OfpFlowStats, 0)
+
+	for _, f := range flows {
+		if !FlowHasOutGroup(f, groupId) {
+			toKeep = append(toKeep, f)
+		}
+	}
+	return len(toKeep) < len(flows), toKeep
+}