diff --git a/core/omci_common.go b/core/omci_common.go
new file mode 100644
index 0000000..d4d2e35
--- /dev/null
+++ b/core/omci_common.go
@@ -0,0 +1,31 @@
+/*
+ * 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 "fmt"
+
+type OmciError struct {
+	Msg string
+}
+
+func (e *OmciError) Error() string {
+	return fmt.Sprintf("%s", e.Msg)
+}
+
+type OnuKey struct {
+	IntfId, OnuId uint32
+}