diff --git a/apps/network-troubleshoot/api/src/main/java/org/onosproject/fnl/intf/NetworkAnomaly.java b/apps/network-troubleshoot/api/src/main/java/org/onosproject/fnl/intf/NetworkAnomaly.java
new file mode 100644
index 0000000..aa754a7
--- /dev/null
+++ b/apps/network-troubleshoot/api/src/main/java/org/onosproject/fnl/intf/NetworkAnomaly.java
@@ -0,0 +1,42 @@
+/*
+ * 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.fnl.intf;
+
+/**
+ * Result of network anomaly diagnosis.
+ */
+public interface NetworkAnomaly {
+
+    /**
+     * Returns the type of anomaly result.
+     *
+     * @return the type of anomaly
+     */
+    Type type();
+
+    /**
+     * Represents anomaly types.
+     */
+    enum Type {
+
+        /**
+         * Packets round among several devices with several forwarding entries.
+         *
+         * Routing loops.
+         */
+        LOOP
+    }
+}