diff --git a/core/openolt_service.go b/core/openolt_service.go
new file mode 100644
index 0000000..3f0c311
--- /dev/null
+++ b/core/openolt_service.go
@@ -0,0 +1,82 @@
+/*
+ * 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 core
+
+import (
+	"gerrit.opencord.org/voltha-bbsim/protos"
+	"gerrit.opencord.org/voltha-bbsim/device"
+	"log"
+)
+
+func sendOltInd(stream openolt.Openolt_EnableIndicationServer, olt *device.Olt) error {
+	data := &openolt.Indication_OltInd{OltInd: &openolt.OltIndication{OperState: "up"}}
+	if err := stream.Send(&openolt.Indication{Data: data}); err != nil {
+		log.Printf("Failed to send OLT indication: %v\n", err)
+		return err
+	}
+	return nil
+}
+
+func sendIntfInd(stream openolt.Openolt_EnableIndicationServer, olt *device.Olt) error {
+	for i := uint32(0); i < olt.NumPonIntf+olt.NumNniIntf; i++ {
+		intf := olt.Intfs[i]
+		data := &openolt.Indication_IntfInd{&openolt.IntfIndication{IntfId: intf.IntfID, OperState: intf.OperState}}
+		if err := stream.Send(&openolt.Indication{Data: data}); err != nil {
+			log.Printf("Failed to send Intf [id: %d] indication : %v\n", i, err)
+			return err
+		}
+		log.Printf("SendIntfInd olt:%d intf:%d (%s)\n", olt.ID, intf.IntfID, intf.Type)
+	}
+	return nil
+}
+
+func sendOperInd(stream openolt.Openolt_EnableIndicationServer, olt *device.Olt) error {
+	for i := uint32(0); i < olt.NumPonIntf+olt.NumNniIntf; i++ {
+		intf := olt.Intfs[i]
+		data := &openolt.Indication_IntfOperInd{&openolt.IntfOperIndication{Type: intf.Type, IntfId: intf.IntfID, OperState: intf.OperState}}
+		if err := stream.Send(&openolt.Indication{Data: data}); err != nil {
+			log.Printf("Failed to send IntfOper [id: %d] indication : %v\n", i, err)
+			return err
+		}
+		log.Printf("SendOperInd olt:%d intf:%d (%s)\n", olt.ID, intf.IntfID, intf.Type)
+	}
+	return nil
+}
+
+func sendOnuDiscInd(stream openolt.Openolt_EnableIndicationServer, onus []*device.Onu) error {
+	for i, onu := range onus {
+		data := &openolt.Indication_OnuDiscInd{&openolt.OnuDiscIndication{IntfId: onu.IntfID, SerialNumber: onu.SerialNumber}}
+		log.Printf("sendONUDiscInd Onuid: %d\n", i)
+		if err := stream.Send(&openolt.Indication{Data: data}); err != nil {
+			log.Printf("Failed to send ONUDiscInd [id: %d]: %v\n", i, err)
+			return err
+		}
+	}
+	return nil
+}
+
+func sendOnuInd(stream openolt.Openolt_EnableIndicationServer, onus []*device.Onu) error {
+	for i, onu := range onus {
+		data := &openolt.Indication_OnuInd{&openolt.OnuIndication{IntfId: onu.IntfID, OnuId: onu.OnuID, OperState: "up", AdminState: "up", SerialNumber: onu.SerialNumber}}
+		log.Printf("sendONUInd Onuid: %d\n", i)
+		if err := stream.Send(&openolt.Indication{Data: data}); err != nil {
+			log.Printf("Failed to send ONUInd [id: %d]: %v\n", i, err)
+			return err
+		}
+	}
+	return nil
+}