diff --git a/protocols/isis/api/src/main/java/org/onosproject/isis/controller/topology/IsisAgent.java b/protocols/isis/api/src/main/java/org/onosproject/isis/controller/topology/IsisAgent.java
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+++ b/protocols/isis/api/src/main/java/org/onosproject/isis/controller/topology/IsisAgent.java
@@ -0,0 +1,53 @@
+/*
+ * 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.isis.controller.topology;
+
+/**
+ * Representation of an ISIS agent.
+ * It is responsible for keeping track of the current set of routers
+ * connected to the system.
+ */
+public interface IsisAgent {
+    /**
+     * Adds a router that has just connected to the system.
+     *
+     * @param isisRouter the router id to add
+     * @return true if added, false otherwise
+     */
+    boolean addConnectedRouter(IsisRouter isisRouter);
+
+    /**
+     * Removes the router which got disconnected from the system.
+     *
+     * @param isisRouter the router id to remove
+     */
+    void removeConnectedRouter(IsisRouter isisRouter);
+
+    /**
+     * Notifies that got a packet of link from network and need do processing.
+     *
+     * @param isisLink  link instance
+     */
+    void addLink(IsisLink isisLink);
+
+    /**
+     * Notifies that got a packet of link from network and need do processing.
+     *
+     * @param isisLink  link instance
+     */
+    void deleteLink(IsisLink isisLink);
+}
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