diff --git a/src/main/java/org/opencord/aaa/impl/CustomizationInfo.java b/src/main/java/org/opencord/aaa/impl/CustomizationInfo.java
new file mode 100644
index 0000000..56f296e
--- /dev/null
+++ b/src/main/java/org/opencord/aaa/impl/CustomizationInfo.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+ *
+ * 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.aaa.impl;
+
+import org.onosproject.net.device.DeviceService;
+import org.opencord.sadis.SubscriberAndDeviceInformationService;
+
+/**
+ * Bindings to Device service and Subscriber and Device Information service
+ * (SADIS), required for RADIUS packet customization.
+ */
+public class CustomizationInfo {
+
+    private final SubscriberAndDeviceInformationService subsService;
+    private final DeviceService devService;
+
+    /**
+     * Creates a customization info instance, with bindings for the given
+     * service instances.
+     *
+     * @param subsService subscriber service
+     * @param devService  device service
+     */
+    public CustomizationInfo(SubscriberAndDeviceInformationService subsService,
+                             DeviceService devService) {
+        this.subsService = subsService;
+        this.devService = devService;
+    }
+
+    /**
+     * Returns the reference to the subscriber service.
+     *
+     * @return the subscriber service
+     */
+    public SubscriberAndDeviceInformationService subscriberService() {
+        return subsService;
+    }
+
+    /**
+     * Returns the reference to the device service.
+     *
+     * @return the device service
+     */
+    public DeviceService deviceService() {
+        return devService;
+    }
+}
diff --git a/src/main/java/org/opencord/aaa/impl/RadiusCommunicator.java b/src/main/java/org/opencord/aaa/impl/RadiusCommunicator.java
new file mode 100644
index 0000000..018ccb8
--- /dev/null
+++ b/src/main/java/org/opencord/aaa/impl/RadiusCommunicator.java
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2017-present Open Networking Foundation
+ *
+ * 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.aaa.impl;
+
+import org.onlab.packet.RADIUS;
+import org.onosproject.net.packet.InboundPacket;
+import org.onosproject.net.packet.PacketContext;
+import org.opencord.aaa.api.AaaConfig;
+
+/**
+ * Interface to the implementations for RADIUS server side communication.
+ */
+public interface RadiusCommunicator {
+
+    /**
+     * Initializes the local state of the communicator, using the relevant
+     * parameters from the supplied configuration.
+     *
+     * @param newCfg new configuration to be applied
+     */
+    void initializeLocalState(AaaConfig newCfg);
+
+    /**
+     * Clears local state.
+     */
+    void clearLocalState();
+
+    /**
+     * Callback invoked when the AAA application is deactivated.
+     */
+    void deactivate();
+
+    /**
+     * Provisions intercepts on the switches (if needed).
+     */
+    void requestIntercepts();
+
+    /**
+     * Clears intercepts from the switches (if needed).
+     */
+    void withdrawIntercepts();
+
+    /**
+     * Sends the given RADIUS packet to the RADIUS server. The incoming
+     * EAPOL packet (from the switch to ONOS) is provided as reference.
+     *
+     * @param radiusPacket RADIUS packet to be sent to server
+     * @param inPkt        incoming EAPOL packet
+     */
+    void sendRadiusPacket(RADIUS radiusPacket, InboundPacket inPkt);
+
+    /**
+     * Handles the packet from RADIUS server.
+     *
+     * @param context incoming packet context
+     */
+    void handlePacketFromServer(PacketContext context);
+}