diff --git a/core/api/src/main/java/org/onosproject/codec/ExtensionSelectorCodec.java b/core/api/src/main/java/org/onosproject/codec/ExtensionSelectorCodec.java
new file mode 100644
index 0000000..fc51216
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/codec/ExtensionSelectorCodec.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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 org.onosproject.codec;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onosproject.net.driver.HandlerBehaviour;
+import org.onosproject.net.flow.criteria.ExtensionSelector;
+
+/**
+ * Interface for encode and decode extension selector.
+ */
+public interface ExtensionSelectorCodec extends HandlerBehaviour {
+
+    /**
+     * Encodes an extension selector to an JSON object.
+     *
+     * @param extensionSelector extension selector
+     * @param  context encoding context
+     * @return JSON object
+     */
+    default ObjectNode encode(ExtensionSelector extensionSelector, CodecContext context) {
+        return null;
+    }
+
+    /**
+     * Decodes an JSON object to an extension selector.
+     *
+     * @param objectNode JSON object
+     * @param  context decoding context
+     * @return extension selector
+     */
+    default ExtensionSelector decode(ObjectNode objectNode, CodecContext context) {
+        return null;
+    }
+}
diff --git a/core/api/src/main/java/org/onosproject/codec/ExtensionTreatmentCodec.java b/core/api/src/main/java/org/onosproject/codec/ExtensionTreatmentCodec.java
new file mode 100644
index 0000000..e33258b
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/codec/ExtensionTreatmentCodec.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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 org.onosproject.codec;
+
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import org.onosproject.net.driver.HandlerBehaviour;
+import org.onosproject.net.flow.instructions.ExtensionTreatment;
+
+/**
+ * Interface for encode and decode extension treatment.
+ */
+public interface ExtensionTreatmentCodec extends HandlerBehaviour {
+
+    /**
+     * Encodes an extension treatment to an JSON object.
+     *
+     * @param extensionTreatment extension treatment
+     * @param  context encoding context
+     * @return JSON object
+     */
+    default ObjectNode encode(ExtensionTreatment extensionTreatment, CodecContext context) {
+        return null;
+    }
+
+    /**
+     * Decodes an JSON object to an extension treatment.
+     *
+     * @param objectNode JSON object
+     * @param  context decoding context
+     * @return extension treatment
+     */
+    default ExtensionTreatment decode(ObjectNode objectNode, CodecContext context) {
+        return null;
+    }
+}
diff --git a/core/api/src/main/java/org/onosproject/net/flow/instructions/ExtensionTreatmentType.java b/core/api/src/main/java/org/onosproject/net/flow/instructions/ExtensionTreatmentType.java
index cf2400c..df9789e 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/instructions/ExtensionTreatmentType.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/instructions/ExtensionTreatmentType.java
@@ -79,6 +79,15 @@
         this.type = type;
     }
 
+    /**
+     * Returns extension treatment type.
+     *
+     * @return extension treatment type
+     */
+    public int type() {
+        return type;
+    }
+
     @Override
     public int hashCode() {
         return Objects.hash(type);