diff --git a/apps/castor/src/main/java/org/onosproject/castor/ArpService.java b/apps/castor/src/main/java/org/onosproject/castor/ArpService.java
new file mode 100644
index 0000000..3df12f8
--- /dev/null
+++ b/apps/castor/src/main/java/org/onosproject/castor/ArpService.java
@@ -0,0 +1,39 @@
+/*
+ * 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.castor;
+
+import org.onosproject.net.packet.PacketContext;
+
+/**
+ * Interface for processing and handling ARP related events.
+ */
+public interface ArpService {
+
+    /**
+     * Creates an ARP packet to probe for the peer's mac address.
+     *
+     * @param peer A Peer
+     */
+    void createArp(Peer peer);
+
+    /**
+     * Handles the ARP packet in.
+     *
+     * @param context packet context to handle
+     * @return true if handled
+     */
+    boolean handlePacket(PacketContext context);
+}