diff --git a/core/api/src/main/java/org/onosproject/net/behaviour/BngProgrammable.java b/core/api/src/main/java/org/onosproject/net/behaviour/BngProgrammable.java
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+++ b/core/api/src/main/java/org/onosproject/net/behaviour/BngProgrammable.java
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+/*
+ * Copyright 2019-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.onosproject.net.behaviour;
+
+import org.onlab.packet.IpAddress;
+import org.onlab.packet.MacAddress;
+import org.onlab.packet.VlanId;
+import org.onlab.util.Identifier;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.net.driver.HandlerBehaviour;
+import org.onosproject.net.pi.runtime.PiCounterCellData;
+
+import java.util.Map;
+
+/**
+ * BNG programmable behavior. Provides means to update device forwarding state
+ * to perform BNG user plane functions (e.g., tunnel termination, accounting,
+ * etc.). An implementation of this API should not write state directly to the
+ * device, but instead, always rely on core ONOS subsystems (e.g.,
+ * FlowRuleService, GroupService, etc).
+ */
+public interface BngProgrammable extends HandlerBehaviour {
+
+    /**
+     * Provision rules to punt BNG control packets to ONOS. Control packets
+     * might include Session Discovery, Authentication, Address Assignment etc.
+     * Apps are expected to call this method as the first one when they are
+     * ready to process attachment connection requests.
+     *
+     * @param appId Application ID of the caller of this API.
+     * @return True if initialized, false otherwise.
+     */
+    boolean init(ApplicationId appId);
+
+    /**
+     * Remove any state previously created by this API for the given application
+     * ID.
+     *
+     * @param appId Application ID of the application using the
+     *              BngProgrammable.
+     * @throws BngProgrammableException while writing on BNG device.
+     */
+    void cleanUp(ApplicationId appId) throws BngProgrammableException;
+
+    /**
+     * Set up the necessary state to enable termination of the attachment
+     * traffic. Make also sure that the state of the given attachment is cleaned
+     * up. If the attachment is active, packets will be forwarded/terminated
+     * after calling this method, if not they will be dropped.
+     *
+     * @param attachmentInfo Attachment information to configure the line
+     *                       termination.
+     * @throws BngProgrammableException while writing on BNG device.
+     */
+    void setupAttachment(Attachment attachmentInfo)
+            throws BngProgrammableException;
+
+    /**
+     * Remove any state associated with the given attachment, including
+     * termination flow rules. Calling this method while an attachment is
+     * generating/receiving traffic, will eventually cause all packets to be
+     * dropped for that attachment.
+     *
+     * @param attachmentInfo Attachment information to remove the line
+     *                       termination.
+     */
+    void removeAttachment(Attachment attachmentInfo);
+
+    /**
+     * Read all counters for a given attachment and returns a map with keys
+     * BngCounterType and values the ones obtained from the device. If a
+     * specific BngCounterType is not found in the map, it means the device does
+     * not support it.
+     *
+     * @param attachmentInfo Attachment information.
+     * @return The counter values of the attachment.
+     * @throws BngProgrammableException while reading from BNG device.
+     */
+    Map<BngCounterType, PiCounterCellData> readCounters(Attachment attachmentInfo)
+            throws BngProgrammableException;
+
+    /**
+     * Read a specific counter value of a specific attachment. If the given
+     * BngCounterType is not supported by the device, returns null.
+     *
+     * @param attachmentInfo Attachment information.
+     * @param counter        The counter to be read.
+     * @return The value of the specific counter.
+     * @throws BngProgrammableException while reading from BNG device.
+     */
+    PiCounterCellData readCounter(Attachment attachmentInfo, BngCounterType counter)
+            throws BngProgrammableException;
+
+    /**
+     * Read the control plane traffic counter of packets punted before
+     * attachment creation (e.g., when an attachment is not created yet). If
+     * unsupported, return null value.
+     *
+     * @return The value of the control traffic counter.
+     * @throws BngProgrammableException while reading from BNG device.
+     */
+    PiCounterCellData readControlTrafficCounter()
+            throws BngProgrammableException;
+
+    /**
+     * Reset the given counter of a specific attachment.
+     *
+     * @param attachmentInfo Attachment information.
+     * @param counter        The counter to be reset.
+     * @throws BngProgrammableException while writing on BNG device.
+     */
+    void resetCounter(Attachment attachmentInfo, BngCounterType counter)
+            throws BngProgrammableException;
+
+    /**
+     * Reset the all the counters of a specific attachment.
+     *
+     * @param attachmentInfo Attachment information.
+     * @throws BngProgrammableException while writing on BNG device.
+     */
+    void resetCounters(Attachment attachmentInfo)
+            throws BngProgrammableException;
+
+    /**
+     * Reset the control plane traffic counter of packets punted before
+     * attachment creation (e.g., when an attachment is not created yet).
+     *
+     * @throws BngProgrammableException while writing on BNG device.
+     */
+    void resetControlTrafficCounter()
+            throws BngProgrammableException;
+
+    /**
+     * Counters to implement BNG accounting. Some of these counters can be
+     * unsupported by the implementations.
+     */
+    enum BngCounterType {
+        /**
+         * Count the received packets in the downstream direction.
+         */
+        DOWNSTREAM_RX,
+
+        /**
+         * Count the transmitted packets in the downstream direction.
+         */
+        DOWNSTREAM_TX,
+
+        /**
+         * Count the dropped packets in the downstream direction.
+         */
+        DOWNSTREAM_DROPPED,
+
+        /**
+         * Count the received packets in the upstream direction.
+         */
+        UPSTREAM_RX,
+
+        /**
+         * Count the transmitted packets in the upstream direction.
+         */
+        UPSTREAM_TX,
+
+        /**
+         * Count the dropped packets in the upstream direction.
+         */
+        UPSTREAM_DROPPED,
+
+        /**
+         * Count the received control plane packets.
+         */
+        CONTROL_PLANE
+    }
+
+    /**
+     * Immutable representation of an attachment in the BNG context. It
+     * identifies a L2/L2.5 tunnel line between the RG and the BNG.
+     */
+    interface Attachment {
+        /**
+         * Get the identifier of the attachment.
+         *
+         * @return The identifier of the attachment.
+         */
+        AttachmentId attachmentId();
+
+        /**
+         * Get the application ID that generated the attachment.
+         *
+         * @return The application ID.
+         */
+        ApplicationId appId();
+
+        /**
+         * Get the VLAN S-tag of the attachment.
+         *
+         * @return The VLAN S-tag of the attachment.
+         */
+        VlanId sTag();
+
+        /**
+         * Get the VLAN C-tag of the attachment.
+         *
+         * @return The VLAN C-tag of the attachment.
+         */
+        VlanId cTag();
+
+        /**
+         * Get the MAC address of the attachment.
+         *
+         * @return The MAC address of the attachment.
+         */
+        MacAddress macAddress();
+
+        /**
+         * Get the IP address of the attachment.
+         *
+         * @return The IP address of the attachment.
+         */
+        IpAddress ipAddress();
+
+        /**
+         * Defines if the line related to the attachment is active.
+         *
+         * @return True if the line is active, False otherwise.
+         */
+        boolean lineActive();
+
+        /**
+         * Get the type of attachment.
+         *
+         * @return type of attachment
+         */
+        AttachmentType type();
+
+        /**
+         * Get the PPPoE session ID of the attachment. This method is meaningful
+         * only if the attachment type is PPPoE.
+         *
+         * @return The PPPoE session ID.
+         */
+        short pppoeSessionId();
+
+        enum AttachmentType {
+            /**
+             * Implemented as PPPoE attachment.
+             */
+            PPPoE,
+
+            /**
+             * Implemented as IPoE attachment.
+             */
+            // TODO: unsupported.
+            IPoE
+        }
+    }
+
+    /**
+     * The identifier of the attachment.
+     */
+    class AttachmentId extends Identifier<Long> {
+        /**
+         * Identifies the attachment at network level.
+         *
+         * @param id long value
+         */
+        public AttachmentId(long id) {
+            super(id);
+        }
+    }
+
+    /**
+     * An exception indicating a an error happened in the BNG programmable
+     * behaviour.
+     */
+    class BngProgrammableException extends Exception {
+        /**
+         * Creates a new exception for the given message.
+         *
+         * @param message message
+         */
+        public BngProgrammableException(String message) {
+            super(message);
+        }
+    }
+}
+
+