diff --git a/src/main/java/org/opencord/cordvtn/api/InstanceService.java b/src/main/java/org/opencord/cordvtn/api/InstanceService.java
new file mode 100644
index 0000000..a8e0f77
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+++ b/src/main/java/org/opencord/cordvtn/api/InstanceService.java
@@ -0,0 +1,57 @@
+/*
+ * 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.opencord.cordvtn.api;
+
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.HostId;
+import org.onosproject.net.host.HostDescription;
+
+/**
+ * Provides service instance addition or removal.
+ */
+public interface InstanceService {
+
+    /**
+     * Adds a service instance on a given connect point.
+     *
+     * @param connectPoint connect point of the instance
+     */
+    void addInstance(ConnectPoint connectPoint);
+
+    /**
+     * Removes a service instance from a given connect point.
+     *
+     * @param connectPoint connect point
+     */
+    void removeInstance(ConnectPoint connectPoint);
+
+    /**
+     * Adds a nested instance with given host ID and host description.
+     * Nested instance can be a container inside a virtual machine, for example.
+     * DHCP is not supported for the nested instance.
+     *
+     * @param hostId host id
+     * @param description host description
+     */
+    void addNestedInstance(HostId hostId, HostDescription description);
+
+    /**
+     * Removes nested instance with a given host ID.
+     *
+     * @param hostId host id
+     */
+    void removeNestedInstance(HostId hostId);
+}