diff --git a/python/extensions/omci/omci_cc.py b/python/extensions/omci/omci_cc.py
new file mode 100644
index 0000000..7d4d304
--- /dev/null
+++ b/python/extensions/omci/omci_cc.py
@@ -0,0 +1,1047 @@
+#
+# 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.
+#
+"""
+OMCI Message support
+"""
+
+import sys
+import arrow
+from twisted.internet import reactor, defer
+from twisted.internet.defer import TimeoutError, CancelledError, failure, fail, succeed, inlineCallbacks
+from common.frameio.frameio import hexify
+from voltha.extensions.omci.omci import *
+from voltha.extensions.omci.omci_me import OntGFrame, OntDataFrame, SoftwareImageFrame
+from voltha.extensions.omci.me_frame import MEFrame
+from voltha.extensions.omci.omci_defs import EntityOperations, ReasonCodes
+from common.event_bus import EventBusClient
+from enum import IntEnum
+from binascii import hexlify
+
+
+def hexify(buffer):
+    """Return a hexadecimal string encoding of input buffer"""
+    return ''.join('%02x' % ord(c) for c in buffer)
+
+
+DEFAULT_OMCI_TIMEOUT = 3                           # Seconds
+MAX_OMCI_REQUEST_AGE = 60                          # Seconds
+DEFAULT_OMCI_DOWNLOAD_SECTION_SIZE = 31            # Bytes
+MAX_TABLE_ROW_COUNT = 512                          # Keep get-next logic reasonable
+
+CONNECTED_KEY = 'connected'
+TX_REQUEST_KEY = 'tx-request'
+RX_RESPONSE_KEY = 'rx-response'
+UNKNOWN_CLASS_ATTRIBUTE_KEY = 'voltha-unknown-blob'
+
+
+class OmciCCRxEvents(IntEnum):
+    AVC_Notification = 0,
+    MIB_Upload = 1,
+    MIB_Upload_Next = 2,
+    Create = 3,
+    Delete = 4,
+    Set = 5,
+    Alarm_Notification = 6,
+    Test_Result = 7,
+    MIB_Reset = 8,
+    Connectivity = 9,
+    Get_ALARM_Get = 10,
+    Get_ALARM_Get_Next = 11
+
+
+# abbreviations
+OP = EntityOperations
+RxEvent = OmciCCRxEvents
+
+
+class OMCI_CC(object):
+    """ Handle OMCI Communication Channel specifics for Adtran ONUs"""
+
+    MIN_OMCI_TX_ID_LOW_PRIORITY = 0x0001  # 2 Octets max
+    MAX_OMCI_TX_ID_LOW_PRIORITY = 0x7FFF  # 2 Octets max
+    MIN_OMCI_TX_ID_HIGH_PRIORITY = 0x8000  # 2 Octets max
+    MAX_OMCI_TX_ID_HIGH_PRIORITY = 0xFFFF  # 2 Octets max
+    LOW_PRIORITY = 0
+    HIGH_PRIORITY = 1
+
+    # Offset into some tuples for pending lists and tx in progress
+    PENDING_DEFERRED = 0
+    PENDING_FRAME = 1
+    PENDING_TIMEOUT = 2
+    PENDING_RETRY = 3
+
+    REQUEST_TIMESTAMP = 0
+    REQUEST_DEFERRED = 1
+    REQUEST_FRAME = 2
+    REQUEST_TIMEOUT = 3
+    REQUEST_RETRY = 4
+    REQUEST_DELAYED_CALL = 5
+
+    _frame_to_event_type = {
+        OmciMibResetResponse.message_id: RxEvent.MIB_Reset,
+        OmciMibUploadResponse.message_id: RxEvent.MIB_Upload,
+        OmciMibUploadNextResponse.message_id: RxEvent.MIB_Upload_Next,
+        OmciCreateResponse.message_id: RxEvent.Create,
+        OmciDeleteResponse.message_id: RxEvent.Delete,
+        OmciSetResponse.message_id: RxEvent.Set,
+        OmciGetAllAlarmsResponse.message_id: RxEvent.Get_ALARM_Get,
+        OmciGetAllAlarmsNextResponse.message_id: RxEvent.Get_ALARM_Get_Next
+    }
+
+    def __init__(self, adapter_agent, device_id, me_map=None,
+                 clock=None):
+        self.log = structlog.get_logger(device_id=device_id)
+        self._adapter_agent = adapter_agent
+        self._device_id = device_id
+        self._proxy_address = None
+        self._enabled = False
+        self._extended_messaging = False
+        self._me_map = me_map
+        if clock is None:
+            self.reactor = reactor
+        else:
+            self.reactor = clock
+
+        # Support 2 levels of priority since only baseline message set supported
+        self._tx_tid = [OMCI_CC.MIN_OMCI_TX_ID_LOW_PRIORITY, OMCI_CC.MIN_OMCI_TX_ID_HIGH_PRIORITY]
+        self._tx_request = [None, None]    # Tx in progress (timestamp, defer, frame, timeout, retry, delayedCall)
+        self._tx_request_deferred = [None, None]    # Tx in progress but held till child Rx/TX can finish. ie omci tables.
+        self._pending = [list(), list()]   # pending queue (deferred, tx_frame, timeout, retry)
+        self._rx_response = [None, None]
+
+        # Statistics
+        self._tx_frames = 0
+        self._rx_frames = 0
+        self._rx_unknown_tid = 0      # Rx OMCI with no Tx TID match
+        self._rx_onu_frames = 0       # Autonomously generated ONU frames
+        self._rx_onu_discards = 0     # Autonomously generated ONU unknown message types
+        self._rx_timeouts = 0
+        self._rx_late = 0             # Frame response received after timeout on Tx
+        self._rx_unknown_me = 0       # Number of managed entities Rx without a decode definition
+        self._tx_errors = 0           # Exceptions during tx request
+        self._consecutive_errors = 0  # Rx & Tx errors in a row, a good RX resets this to 0
+        self._reply_min = sys.maxint  # Fastest successful tx -> rx
+        self._reply_max = 0           # Longest successful tx -> rx
+        self._reply_sum = 0.0         # Total seconds for successful tx->rx (float for average)
+        self._max_hp_tx_queue = 0     # Maximum size of high priority tx pending queue
+        self._max_lp_tx_queue = 0     # Maximum size of low priority tx pending queue
+
+        self.event_bus = EventBusClient()
+
+        # If a list of custom ME Entities classes were provided, insert them into
+        # main class_id to entity map.
+        # TODO: If this class becomes hidden from the ONU DA, move this to the OMCI State Machine runner
+
+    def __str__(self):
+        return "OMCISupport: {}".format(self._device_id)
+
+    def _get_priority_index(self, high_priority):
+        """ Centralized logic to help make extended message support easier in the future"""
+        return OMCI_CC.HIGH_PRIORITY if high_priority and not self._extended_messaging \
+            else OMCI_CC.LOW_PRIORITY
+
+    def _tid_is_high_priority(self, tid):
+        """ Centralized logic to help make extended message support easier in the future"""
+
+        return not self._extended_messaging and \
+            OMCI_CC.MIN_OMCI_TX_ID_HIGH_PRIORITY <= tid <= OMCI_CC.MAX_OMCI_TX_ID_HIGH_PRIORITY
+
+    @staticmethod
+    def event_bus_topic(device_id, event):
+        """
+        Get the topic name for a given event Frame Type
+        :param device_id: (str) ONU Device ID
+        :param event: (OmciCCRxEvents) Type of event
+        :return: (str) Topic string
+        """
+        assert event in OmciCCRxEvents, \
+            'Event {} is not an OMCI-CC Rx Event'.format(event.name)
+
+        return 'omci-rx:{}:{}'.format(device_id, event.name)
+
+    @property
+    def enabled(self):
+        return self._enabled
+
+    @enabled.setter
+    def enabled(self, value):
+        """
+        Enable/disable the OMCI Communications Channel
+
+        :param value: (boolean) True to enable, False to disable
+        """
+        assert isinstance(value, bool), 'enabled is a boolean'
+
+        if self._enabled != value:
+            self._enabled = value
+            if self._enabled:
+                self._start()
+            else:
+                self._stop()
+
+    @property
+    def tx_frames(self):
+        return self._tx_frames
+
+    @property
+    def rx_frames(self):
+        return self._rx_frames
+
+    @property
+    def rx_unknown_tid(self):
+        return self._rx_unknown_tid         # Tx TID not found
+
+    @property
+    def rx_unknown_me(self):
+        return self._rx_unknown_me
+
+    @property
+    def rx_onu_frames(self):
+        return self._rx_onu_frames
+
+    @property
+    def rx_onu_discards(self):
+        return self._rx_onu_discards        # Attribute Value change autonomous overflows
+
+    @property
+    def rx_timeouts(self):
+        return self._rx_timeouts
+
+    @property
+    def rx_late(self):
+        return self._rx_late
+
+    @property
+    def tx_errors(self):
+        return self._tx_errors
+
+    @property
+    def consecutive_errors(self):
+        return self._consecutive_errors
+
+    @property
+    def reply_min(self):
+        return int(round(self._reply_min * 1000.0))     # Milliseconds
+
+    @property
+    def reply_max(self):
+        return int(round(self._reply_max * 1000.0))     # Milliseconds
+
+    @property
+    def reply_average(self):
+        avg = self._reply_sum / self._rx_frames if self._rx_frames > 0 else 0.0
+        return int(round(avg * 1000.0))     # Milliseconds
+
+    @property
+    def hp_tx_queue_len(self):
+        return len(self._pending[OMCI_CC.HIGH_PRIORITY])
+
+    @property
+    def lp_tx_queue_len(self):
+        return len(self._pending[OMCI_CC.LOW_PRIORITY])
+
+    @property
+    def max_hp_tx_queue(self):
+        return self._max_hp_tx_queue
+
+    @property
+    def max_lp_tx_queue(self):
+        return self._max_lp_tx_queue
+
+    def _start(self):
+        """
+        Start the OMCI Communications Channel
+        """
+        assert self._enabled, 'Start should only be called if enabled'
+        self.flush()
+
+        device = self._adapter_agent.get_device(self._device_id)
+        self._proxy_address = device.proxy_address
+
+    def _stop(self):
+        """
+        Stop the OMCI Communications Channel
+        """
+        assert not self._enabled, 'Stop should only be called if disabled'
+        self.flush()
+        self._proxy_address = None
+
+    def _receive_onu_message(self, rx_frame):
+        """ Autonomously generated ONU frame Rx handler"""
+        self.log.debug('rx-onu-frame', frame_type=type(rx_frame),
+                       frame=hexify(str(rx_frame)))
+
+        msg_type = rx_frame.fields['message_type']
+        self._rx_onu_frames += 1
+
+        msg = {TX_REQUEST_KEY: None,
+               RX_RESPONSE_KEY: rx_frame}
+
+        if msg_type == EntityOperations.AlarmNotification.value:
+            topic = OMCI_CC.event_bus_topic(self._device_id, RxEvent.Alarm_Notification)
+            self.reactor.callLater(0,  self.event_bus.publish, topic, msg)
+
+        elif msg_type == EntityOperations.AttributeValueChange.value:
+            topic = OMCI_CC.event_bus_topic(self._device_id, RxEvent.AVC_Notification)
+            self.reactor.callLater(0,  self.event_bus.publish, topic, msg)
+
+        elif msg_type == EntityOperations.TestResult.value:
+            topic = OMCI_CC.event_bus_topic(self._device_id, RxEvent.Test_Result)
+            self.reactor.callLater(0,  self.event_bus.publish, topic, msg)
+
+        else:
+            self.log.warn('onu-unsupported-autonomous-message', type=msg_type)
+            self._rx_onu_discards += 1
+
+    def _update_rx_tx_stats(self, now, ts):
+        ts_diff = now - arrow.Arrow.utcfromtimestamp(ts)
+        secs = ts_diff.total_seconds()
+        self._reply_sum += secs
+        if secs < self._reply_min:
+            self._reply_min = secs
+        if secs > self._reply_max:
+            self._reply_max = secs
+        return secs
+
+    def receive_message(self, msg):
+        """
+        Receive and OMCI message from the proxy channel to the OLT.
+
+        Call this from your ONU Adapter on a new OMCI Rx on the proxy channel
+        :param msg: (str) OMCI binary message (used as input to Scapy packet decoder)
+        """
+        if not self.enabled:
+            return
+
+        try:
+            now = arrow.utcnow()
+            d = None
+
+            # NOTE: Since we may need to do an independent ME map on a per-ONU basis
+            #       save the current value of the entity_id_to_class_map, then
+            #       replace it with our custom one before decode, and then finally
+            #       restore it later. Tried other ways but really made the code messy.
+            saved_me_map = omci_entities.entity_id_to_class_map
+            omci_entities.entity_id_to_class_map = self._me_map
+
+            try:
+                rx_frame = msg if isinstance(msg, OmciFrame) else OmciFrame(msg)
+                rx_tid = rx_frame.fields['transaction_id']
+
+                if rx_tid == 0:
+                    return self._receive_onu_message(rx_frame)
+
+                # Previously unreachable if this is the very first Rx or we
+                # have been running consecutive errors
+                if self._rx_frames == 0 or self._consecutive_errors != 0:
+                    self.reactor.callLater(0, self._publish_connectivity_event, True)
+
+                self._rx_frames += 1
+                self._consecutive_errors = 0
+
+            except KeyError as e:
+                # Unknown, Unsupported, or vendor-specific ME. Key is the unknown classID
+                self.log.debug('frame-decode-key-error', msg=hexlify(msg), e=e)
+                rx_frame = self._decode_unknown_me(msg)
+                self._rx_unknown_me += 1
+                rx_tid = rx_frame.fields.get('transaction_id')
+
+            except Exception as e:
+                self.log.exception('frame-decode', msg=hexlify(msg), e=e)
+                return
+
+            finally:
+                omci_entities.entity_id_to_class_map = saved_me_map     # Always restore it.
+
+            try:
+                high_priority = self._tid_is_high_priority(rx_tid)
+                index = self._get_priority_index(high_priority)
+
+                # (timestamp, defer, frame, timeout, retry, delayedCall)
+                last_tx_tuple = self._tx_request[index]
+
+                if last_tx_tuple is None or \
+                        last_tx_tuple[OMCI_CC.REQUEST_FRAME].fields.get('transaction_id') != rx_tid:
+                    # Possible late Rx on a message that timed-out
+                    self._rx_unknown_tid += 1
+                    #self.log.warn('tx-message-missing', rx_id=rx_tid, msg=hexlify(msg))
+                    #return
+
+                ts, d, tx_frame, timeout, retry, dc = last_tx_tuple
+                if dc is not None and not dc.cancelled and not dc.called:
+                    dc.cancel()
+                    # self.log.debug("cancel-timeout-called")
+
+                secs = self._update_rx_tx_stats(now, ts)
+
+                # Late arrival already serviced by a timeout?
+                if d.called:
+                    self._rx_late += 1
+                    return
+
+            except Exception as e:
+                self.log.exception('frame-match', msg=hexlify(msg), e=e)
+                if d is not None:
+                    return d.errback(failure.Failure(e))
+                return
+
+            # Extended processing needed. Note 'data' field will be None on some error
+            # status returns
+            omci_msg = rx_frame.fields['omci_message']
+
+            if isinstance(omci_msg, OmciGetResponse) and \
+                    omci_msg.fields.get('data') is not None and \
+                    'table_attribute_mask' in omci_msg.fields['data']:
+                # Yes, run in a separate generator
+                reactor.callLater(0, self._process_get_rx_frame, timeout, secs,
+                                  rx_frame, d, tx_frame, high_priority)
+            else:
+                # Publish Rx event to listeners in a different task
+                reactor.callLater(0, self._publish_rx_frame, tx_frame, rx_frame)
+
+                # begin success callback chain (will cancel timeout and queue next Tx message)
+                from copy import copy
+                original_callbacks = copy(d.callbacks)
+                self._rx_response[index] = rx_frame
+                d.callback(rx_frame)
+
+        except Exception as e:
+            self.log.exception('rx-msg', e=e)
+
+    @inlineCallbacks
+    def _process_get_rx_frame(self, timeout, secs, rx_frame, d, tx_frame, high_priority):
+        """
+        Special handling for Get Requests that may require additional 'get_next' operations
+        if a table attribute was requested.
+        """
+        omci_msg = rx_frame.fields['omci_message']
+        rx_tid = rx_frame.fields.get('transaction_id')
+        high_priority = self._tid_is_high_priority(rx_tid)
+        frame_index = self._get_priority_index(high_priority)
+
+        if isinstance(omci_msg, OmciGetResponse) and 'table_attribute_mask' in omci_msg.fields['data']:
+
+            # save tx request for later so that below send/recv can finish
+            self._tx_request_deferred[frame_index] = self._tx_request[frame_index]
+            self._tx_request[frame_index] = None
+
+            try:
+                entity_class = omci_msg.fields['entity_class']
+                entity_id = omci_msg.fields['entity_id']
+                table_attributes = omci_msg.fields['data']['table_attribute_mask']
+
+                # Table attribute mask is encoded opposite of managed entity mask.
+                if entity_class in self._me_map:
+                    ec = self._me_map[entity_class]
+                    for index in xrange(1, len(ec.attributes) + 1):
+                        attr_mask = 1 << index
+
+                        if attr_mask & table_attributes:
+                            self.log.debug('omcc-get-table-ec', ec=ec, index=index, attr_mask=attr_mask,
+                                           table_attributes=table_attributes)
+                            eca = ec.attributes[index]
+                            self.log.debug('omcc-get-table-attribute', table_name=eca.field.name)
+
+                            seq_no = 0
+                            data_buffer = ''
+                            count = omci_msg.fields['data'][eca.field.name + '_size']
+
+                            if count > MAX_TABLE_ROW_COUNT:
+                                self.log.error('omcc-get-table-huge', count=count, name=eca.field.name)
+                                raise ValueError('Huge Table Size: {}'.format(count))
+
+                            # Original timeout must be chopped up into each individual get-next request
+                            # in order for total transaction to complete within the timeframe of the
+                            # original get() timeout.
+                            number_transactions = 1 + (count + OmciTableField.PDU_SIZE - 1) / OmciTableField.PDU_SIZE
+                            timeout /= (1 + number_transactions)
+
+                            # Start the loop
+                            vals = []
+                            for offset in xrange(0, count, OmciTableField.PDU_SIZE):
+                                frame = MEFrame(ec, entity_id, {eca.field.name: seq_no}).get_next()
+                                seq_no += 1
+
+                                max_retries = 3
+                                results = yield self.send(frame, min(timeout / max_retries, secs * 3), max_retries)
+
+                                omci_getnext_msg = results.fields['omci_message']
+                                status = omci_getnext_msg.fields['success_code']
+
+                                if status != ReasonCodes.Success.value:
+                                    raise Exception('get-next-failure table=' + eca.field.name +
+                                                    ' entity_id=' + str(entity_id) +
+                                                    ' sqn=' + str(seq_no) + ' omci-status ' + str(status))
+
+                                # Extract the data
+                                num_octets = count - offset
+                                if num_octets > OmciTableField.PDU_SIZE:
+                                    num_octets = OmciTableField.PDU_SIZE
+
+                                data = omci_getnext_msg.fields['data'][eca.field.name]
+                                data_buffer += data[:num_octets]
+
+                            while data_buffer:
+                                data_buffer, val = eca.field.getfield(None, data_buffer)
+                                vals.append(val)
+
+                            omci_msg.fields['data'][eca.field.name] = vals
+                            del omci_msg.fields['data'][eca.field.name + '_size']
+                            self.log.debug('omcc-got-table-attribute-rows', table_name=eca.field.name,
+                                           row_count=len(vals))
+                del omci_msg.fields['data']['table_attribute_mask']
+
+            except Exception as e:
+                self.log.exception('get-next-error', e=e)
+                self._tx_request_deferred[frame_index] = None
+                d.errback(failure.Failure(e), high_priority)
+                return
+
+            except IndexError as e:
+                self.log.exception('get-next-index-error', e=e)
+                self._tx_request_deferred[frame_index] = None
+                d.errback(failure.Failure(e), high_priority)
+                return
+
+            # Put it back so the outer Rx/Tx can finish
+            self._tx_request[frame_index] = self._tx_request_deferred[frame_index]
+            self._tx_request_deferred[frame_index] = None
+
+        # Publish Rx event to listeners in a different task
+        if not isinstance(omci_msg, OmciGetNextResponse):
+            reactor.callLater(0, self._publish_rx_frame, tx_frame, rx_frame)
+
+        from copy import copy
+        original_callbacks = copy(d.callbacks)
+        self._rx_response[frame_index] = rx_frame
+        d.callback(rx_frame)
+        self.log.debug("finished-processing-get-rx-frame")
+
+    def _decode_unknown_me(self, msg):
+        """
+        Decode an ME for an unsupported class ID.  This should only occur for a subset
+        of message types (Get, Set, MIB Upload Next, ...) and they should only be
+        responses as well.
+
+        There are some times below that are commented out. For VOLTHA 2.0, it is
+        expected that any get, set, create, delete for unique (often vendor) MEs
+        will be coded by the ONU utilizing it and supplied to OpenOMCI as a
+        vendor-specific ME during device initialization.
+
+        :param msg: (str) Binary data
+        :return: (OmciFrame) resulting frame
+        """
+        from struct import unpack
+
+        (tid, msg_type, framing) = unpack('!HBB', msg[0:4])
+
+        assert framing == 0xa, 'Only basic OMCI framing supported at this time'
+        msg = msg[4:]
+
+        # TODO: Commented out items below are future work (not expected for VOLTHA v2.0)
+        (msg_class, kwargs) = {
+            # OmciCreateResponse.message_id: (OmciCreateResponse, None),
+            # OmciDeleteResponse.message_id: (OmciDeleteResponse, None),
+            # OmciSetResponse.message_id: (OmciSetResponse, None),
+            # OmciGetResponse.message_id: (OmciGetResponse, None),
+            # OmciGetAllAlarmsNextResponse.message_id: (OmciGetAllAlarmsNextResponse, None),
+            OmciMibUploadNextResponse.message_id: (OmciMibUploadNextResponse,
+                                                   {
+                                                       'entity_class': unpack('!H', msg[0:2])[0],
+                                                       'entity_id': unpack('!H', msg[2:4])[0],
+                                                       'object_entity_class': unpack('!H', msg[4:6])[0],
+                                                       'object_entity_id': unpack('!H', msg[6:8])[0],
+                                                       'object_attributes_mask': unpack('!H', msg[8:10])[0],
+                                                       'object_data': {
+                                                           UNKNOWN_CLASS_ATTRIBUTE_KEY: hexlify(msg[10:-4])
+                                                       },
+                                                   }),
+            # OmciAlarmNotification.message_id: (OmciAlarmNotification, None),
+            OmciAttributeValueChange.message_id: (OmciAttributeValueChange,
+                                                   {
+                                                       'entity_class': unpack('!H', msg[0:2])[0],
+                                                       'entity_id': unpack('!H', msg[2:4])[0],
+                                                       'data': {
+                                                           UNKNOWN_CLASS_ATTRIBUTE_KEY: hexlify(msg[4:-8])
+                                                       },
+                                                   }),
+            # OmciTestResult.message_id: (OmciTestResult, None),
+        }.get(msg_type, None)
+
+        if msg_class is None:
+            raise TypeError('Unsupport Message Type for Unknown Decode: {}',
+                            msg_type)
+
+        return OmciFrame(transaction_id=tid, message_type=msg_type,
+                         omci_message=msg_class(**kwargs))
+
+    def _publish_rx_frame(self, tx_frame, rx_frame):
+        """
+        Notify listeners of successful response frame
+        :param tx_frame: (OmciFrame) Original request frame
+        :param rx_frame: (OmciFrame) Response frame
+        """
+        if self._enabled and isinstance(rx_frame, OmciFrame):
+            frame_type = rx_frame.fields['omci_message'].message_id
+            event_type = OMCI_CC._frame_to_event_type.get(frame_type)
+
+            if event_type is not None:
+                topic = OMCI_CC.event_bus_topic(self._device_id, event_type)
+                msg = {TX_REQUEST_KEY: tx_frame,
+                       RX_RESPONSE_KEY: rx_frame}
+
+                self.event_bus.publish(topic=topic, msg=msg)
+
+    def _publish_connectivity_event(self, connected):
+        """
+        Notify listeners of Rx/Tx connectivity over OMCI
+        :param connected: (bool) True if connectivity transitioned from unreachable
+                                 to reachable
+        """
+        if self._enabled:
+            topic = OMCI_CC.event_bus_topic(self._device_id,
+                                            RxEvent.Connectivity)
+            msg = {CONNECTED_KEY: connected}
+            self.event_bus.publish(topic=topic, msg=msg)
+
+    def flush(self):
+        """Flush/cancel in active or pending Tx requests"""
+        requests = []
+
+        for priority in {OMCI_CC.HIGH_PRIORITY, OMCI_CC.LOW_PRIORITY}:
+            next_frame, self._tx_request[priority] = self._tx_request[priority], None
+            if next_frame is not None:
+                requests.append((next_frame[OMCI_CC.REQUEST_DEFERRED], next_frame[OMCI_CC.REQUEST_DELAYED_CALL]))
+
+            requests += [(next_frame[OMCI_CC.PENDING_DEFERRED], None)
+                         for next_frame in self._pending[priority]]
+            self._pending[priority] = list()
+
+        # Cancel them...
+        def cleanup_unhandled_error(_):
+            pass    # So the cancel below does not flag an unhandled error
+
+        for d, dc in requests:
+            if d is not None and not d.called:
+                d.addErrback(cleanup_unhandled_error)
+                d.cancel()
+
+            if dc is not None and not dc.called and not dc.cancelled:
+                dc.cancel()
+
+    def _get_tx_tid(self, high_priority=False):
+        """
+        Get the next Transaction ID for a tx.  Note TID=0 is reserved
+        for autonomously generated messages from an ONU
+
+        :return: (int) TID
+        """
+        if self._extended_messaging or not high_priority:
+            index = OMCI_CC.LOW_PRIORITY
+            min_tid = OMCI_CC.MIN_OMCI_TX_ID_LOW_PRIORITY
+            max_tid = OMCI_CC.MAX_OMCI_TX_ID_LOW_PRIORITY
+        else:
+            index = OMCI_CC.HIGH_PRIORITY
+            min_tid = OMCI_CC.MIN_OMCI_TX_ID_HIGH_PRIORITY
+            max_tid = OMCI_CC.MAX_OMCI_TX_ID_HIGH_PRIORITY
+
+        tx_tid, self._tx_tid[index] = self._tx_tid[index], self._tx_tid[index] + 1
+
+        if self._tx_tid[index] > max_tid:
+            self._tx_tid[index] = min_tid
+
+        return tx_tid
+
+    def _request_failure(self, value, tx_tid, high_priority):
+        """
+        Handle a transmit failure. Rx Timeouts are handled on the 'dc' deferred and
+        will call a different method that may retry if requested.  This routine
+        will be called after the final (if any) timeout or other error
+
+        :param value: (Failure) Twisted failure
+        :param tx_tid: (int) Associated Tx TID
+        """
+        index = self._get_priority_index(high_priority)
+
+        if self._tx_request[index] is not None:
+            tx_frame = self._tx_request[index][OMCI_CC.REQUEST_FRAME]
+            tx_frame_tid = tx_frame.fields['transaction_id']
+
+            if tx_frame_tid == tx_tid:
+                timeout = self._tx_request[index][OMCI_CC.REQUEST_TIMEOUT]
+                dc = self._tx_request[index][OMCI_CC.REQUEST_DELAYED_CALL]
+                self._tx_request[index] = None
+
+                if dc is not None and not dc.called and not dc.cancelled:
+                    dc.cancel()
+
+                if isinstance(value, failure.Failure):
+                    value.trap(CancelledError)
+                    self._rx_timeouts += 1
+                    self._consecutive_errors += 1
+                    if self._consecutive_errors == 1:
+                        reactor.callLater(0, self._publish_connectivity_event, False)
+
+                    self.log.debug('timeout', tx_id=tx_tid, timeout=timeout)
+                    value = failure.Failure(TimeoutError(timeout, "Deferred"))
+            else:
+                # Search pending queue. This may be a cancel coming in from the original
+                # task that requested the Tx.  If found, remove
+                # from pending queue
+                for index, request in enumerate(self._pending[index]):
+                    req = request.get(OMCI_CC.PENDING_DEFERRED)
+                    if req is not None and req.fields['transaction_id'] == tx_tid:
+                        self._pending[index].pop(index)
+                        break
+
+        self._send_next_request(high_priority)
+        return value
+
+    def _request_success(self, rx_frame, high_priority):
+        """
+        Handle transmit success (a matching Rx was received)
+
+        :param rx_frame: (OmciFrame) OMCI response frame with matching TID
+        :return: (OmciFrame) OMCI response frame with matching TID
+        """
+        index = self._get_priority_index(high_priority)
+
+        if rx_frame is None:
+            rx_frame = self._rx_response[index]
+
+        rx_tid = rx_frame.fields.get('transaction_id')
+
+        if rx_tid is not None:
+            if self._tx_request[index] is not None:
+                tx_frame = self._tx_request[index][OMCI_CC.REQUEST_FRAME]
+                tx_tid = tx_frame.fields['transaction_id']
+
+                if rx_tid == tx_tid:
+                    # Remove this request. Next callback in chain initiates next Tx
+                    self._tx_request[index] = None
+                else:
+                    self._rx_late += 1
+            else:
+                self._rx_late += 1
+
+        self._send_next_request(high_priority)
+
+        # Return rx_frame (to next item in callback list)
+        return rx_frame
+
+    def _request_timeout(self, tx_tid, high_priority):
+        """
+        Tx Request timed out.  Resend immediately if there retries is non-zero.  A
+        separate deferred (dc) is used on each actual Tx which is not the deferred
+        (d) that is returned to the caller of the 'send()' method.
+
+        If the timeout if the transmitted frame was zero, this is just cleanup of
+        that transmit request and not necessarily a transmit timeout
+
+        :param tx_tid: (int) TID of frame
+        :param high_priority: (bool) True if high-priority queue
+        """
+        self.log.debug("_request_timeout", tx_tid=tx_tid)
+        index = self._get_priority_index(high_priority)
+
+        if self._tx_request[index] is not None:
+            # (0: timestamp, 1: defer, 2: frame, 3: timeout, 4: retry, 5: delayedCall)
+            ts, d, frame, timeout, retry, _dc = self._tx_request[index]
+
+            if frame.fields.get('transaction_id', 0) == tx_tid:
+                self._tx_request[index] = None
+
+                if timeout > 0:
+                    self._rx_timeouts += 1
+
+                    if retry > 0:
+                        # Push on front of TX pending queue so that it transmits next with the
+                        # original TID
+                        self._queue_frame(d, frame, timeout, retry - 1, high_priority, front=True)
+
+                    elif not d.called:
+                        d.errback(failure.Failure(TimeoutError(timeout, "Send OMCI TID -{}".format(tx_tid))))
+            else:
+                self.log.warn('timeout-but-not-the-tx-frame')  # Statement mainly for debugging
+
+        self._send_next_request(high_priority)
+
+    def _queue_frame(self, d, frame, timeout, retry, high_priority, front=False):
+        index = self._get_priority_index(high_priority)
+        tx_tuple = (d, frame, timeout, retry)        # Pending -> (deferred, tx_frame, timeout, retry)
+
+        if front:
+            self._pending[index].insert(0, tuple)
+        else:
+            self._pending[index].append(tx_tuple)
+
+        # Monitor queue stats
+        qlen = len(self._pending[index])
+
+        if high_priority:
+            if self._max_hp_tx_queue < qlen:
+                self._max_hp_tx_queue = qlen
+
+        elif self._max_lp_tx_queue < qlen:
+            self._max_lp_tx_queue = qlen
+
+        self.log.debug("queue-size", index=index, pending_qlen=qlen)
+
+    def send(self, frame, timeout=DEFAULT_OMCI_TIMEOUT, retry=0, high_priority=False):
+        """
+        Queue the OMCI Frame for a transmit to the ONU via the proxy_channel
+
+        :param frame: (OMCIFrame) Message to send
+        :param timeout: (int) Rx Timeout. 0=No response needed
+        :param retry: (int) Additional retry attempts on channel failure, default=0
+        :param high_priority: (bool) High Priority requests
+        :return: (deferred) A deferred that fires when the response frame is received
+                            or if an error/timeout occurs
+        """
+        if not self.enabled or self._proxy_address is None:
+            # TODO custom exceptions throughout this code would be helpful
+            self._tx_errors += 1
+            return fail(result=failure.Failure(Exception('OMCI is not enabled')))
+
+        timeout = float(timeout)
+        if timeout > float(MAX_OMCI_REQUEST_AGE):
+            self._tx_errors += 1
+            msg = 'Maximum timeout is {} seconds'.format(MAX_OMCI_REQUEST_AGE)
+            return fail(result=failure.Failure(Exception(msg)))
+
+        if not isinstance(frame, OmciFrame):
+            self._tx_errors += 1
+            msg = "Invalid frame class '{}'".format(type(frame))
+            return fail(result=failure.Failure(Exception(msg)))
+        try:
+            index = self._get_priority_index(high_priority)
+            tx_tid = frame.fields['transaction_id']
+
+            if tx_tid is None:
+                tx_tid = self._get_tx_tid(high_priority=high_priority)
+                frame.fields['transaction_id'] = tx_tid
+
+            assert tx_tid not in self._pending[index], 'TX TID {} is already exists'.format(tx_tid)
+            assert tx_tid > 0, 'Invalid Tx TID: {}'.format(tx_tid)
+
+            # Queue it and request next Tx if tx channel is free
+            d = defer.Deferred()
+
+            self._queue_frame(d, frame, timeout, retry, high_priority, front=False)
+            self._send_next_request(high_priority)
+
+            if timeout == 0:
+                self.log.debug("send-timeout-zero", tx_tid=tx_tid)
+                self.reactor.callLater(0, d.callback, 'queued')
+
+            return d
+
+        except Exception as e:
+            self._tx_errors += 1
+            self._consecutive_errors += 1
+
+            if self._consecutive_errors == 1:
+                self.reactor.callLater(0, self._publish_connectivity_event, False)
+
+            self.log.exception('send-omci', e=e)
+            return fail(result=failure.Failure(e))
+
+    def _ok_to_send(self, tx_request, high_priority):
+        """
+        G.988 specifies not to issue a MIB upload or a Software download request
+        when a similar action is in progress on the other channel. To keep the
+        logic here simple, a new upload/download will not be allowed if either a
+        upload/download is going on
+
+        :param tx_request (OmciFrame) Frame to send
+        :param high_priority: (bool) for queue selection
+        :return: True if okay to dequeue and send frame
+        """
+        other = self._get_priority_index(not high_priority)
+
+        if self._tx_request[other] is None:
+            return True
+
+        this_msg_type = tx_request.fields['message_type'] & 0x1f
+        not_allowed = {OP.MibUpload.value,
+                       OP.MibUploadNext.value,
+                       OP.StartSoftwareDownload.value,
+                       OP.DownloadSection.value,
+                       OP.EndSoftwareDownload.value}
+
+        if this_msg_type not in not_allowed:
+            return True
+
+        other_msg_type = self._tx_request[other][OMCI_CC.REQUEST_FRAME].fields['message_type'] & 0x1f
+        return other_msg_type not in not_allowed
+
+    def _send_next_request(self, high_priority):
+        """
+        Pull next tx request and send it
+
+        :param high_priority: (bool) True if this was a high priority request
+        :return: results, so callback chain continues if needed
+        """
+        index = self._get_priority_index(high_priority)
+
+        if self._tx_request[index] is None:  # TODO or self._tx_request[index][OMCI_CC.REQUEST_DEFERRED].called:
+            d = None
+            try:
+                if len(self._pending[index]) and \
+                        not self._ok_to_send(self._pending[index][0][OMCI_CC.PENDING_FRAME],
+                                             high_priority):
+                    reactor.callLater(0.05, self._send_next_request, high_priority)
+                    return
+
+                next_frame = self._pending[index].pop(0)
+
+                d = next_frame[OMCI_CC.PENDING_DEFERRED]
+                frame = next_frame[OMCI_CC.PENDING_FRAME]
+                timeout = next_frame[OMCI_CC.PENDING_TIMEOUT]
+                retry = next_frame[OMCI_CC.PENDING_RETRY]
+
+                tx_tid = frame.fields['transaction_id']
+
+                # NOTE: Since we may need to do an independent ME map on a per-ONU basis
+                #       save the current value of the entity_id_to_class_map, then
+                #       replace it with our custom one before decode, and then finally
+                #       restore it later. Tried other ways but really made the code messy.
+                saved_me_map = omci_entities.entity_id_to_class_map
+                omci_entities.entity_id_to_class_map = self._me_map
+
+                ts = arrow.utcnow().float_timestamp
+                try:
+                    self._rx_response[index] = None
+                    self._adapter_agent.send_proxied_message(self._proxy_address,
+                                                             hexify(str(frame)))
+                finally:
+                    omci_entities.entity_id_to_class_map = saved_me_map
+
+                self._tx_frames += 1
+
+                # Note: the 'd' deferred in the queued request we just got will
+                # already have its success callback queued (callLater -> 0) with a
+                # result of "queued".  Here we need time it out internally so
+                # we can call cleanup appropriately. G.988 mentions that most ONUs
+                # will process an request in < 1 second.
+                dc_timeout = timeout if timeout > 0 else 1.0
+
+                # Timeout on internal deferred to support internal retries if requested
+                dc = self.reactor.callLater(dc_timeout, self._request_timeout, tx_tid, high_priority)
+
+                # (timestamp, defer, frame, timeout, retry, delayedCall)
+                self._tx_request[index] = (ts, d, frame, timeout, retry, dc)
+
+                if timeout > 0:
+                    d.addCallbacks(self._request_success, self._request_failure,
+                                   callbackArgs=(high_priority,),
+                                   errbackArgs=(tx_tid, high_priority))
+
+            except IndexError:
+                pass    # Nothing pending in this queue
+
+            except Exception as e:
+                self.log.exception('send-proxy-exception', e=e)
+                self._tx_request[index] = None
+                self.reactor.callLater(0, self._send_next_request, high_priority)
+
+                if d is not None:
+                    d.errback(failure.Failure(e))
+        else:
+            self.log.debug("tx-request-occupied", index=index)
+
+    ###################################################################################
+    # MIB Action shortcuts
+
+    def send_mib_reset(self, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        """
+        Perform a MIB Reset
+        """
+        self.log.debug('send-mib-reset')
+
+        frame = OntDataFrame().mib_reset()
+        return self.send(frame, timeout=timeout, high_priority=high_priority)
+
+    def send_mib_upload(self, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        self.log.debug('send-mib-upload')
+
+        frame = OntDataFrame().mib_upload()
+        return self.send(frame, timeout=timeout, high_priority=high_priority)
+
+    def send_mib_upload_next(self, seq_no, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        self.log.debug('send-mib-upload-next')
+
+        frame = OntDataFrame(sequence_number=seq_no).mib_upload_next()
+        return self.send(frame, timeout=timeout, high_priority=high_priority)
+
+    def send_reboot(self, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        """
+        Send an ONU Device reboot request (ONU-G ME).
+
+        NOTICE: This method is being deprecated and replaced with a tasks to preform this function
+        """
+        self.log.debug('send-mib-reboot')
+
+        frame = OntGFrame().reboot()
+        return self.send(frame, timeout=timeout, high_priority=high_priority)
+
+    def send_get_all_alarm(self, alarm_retrieval_mode=0, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        self.log.debug('send_get_alarm')
+
+        frame = OntDataFrame().get_all_alarm(alarm_retrieval_mode)
+        return self.send(frame, timeout=timeout, high_priority=high_priority)
+
+    def send_get_all_alarm_next(self, seq_no, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        self.log.debug('send_get_alarm_next')
+
+        frame = OntDataFrame().get_all_alarm_next(seq_no)
+        return self.send(frame, timeout=timeout, high_priority=high_priority)
+
+    def send_start_software_download(self, image_inst_id, image_size, window_size, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        frame = SoftwareImageFrame(image_inst_id).start_software_download(image_size, window_size-1)
+        return self.send(frame, timeout, 3, high_priority=high_priority)
+        
+    def send_download_section(self, image_inst_id, section_num, data, size=DEFAULT_OMCI_DOWNLOAD_SECTION_SIZE, timeout=0, high_priority=False):
+        """
+        # timeout=0 indicates no repons needed
+        """
+        # self.log.debug("send_download_section", instance_id=image_inst_id, section=section_num, timeout=timeout)
+        if timeout > 0:
+            frame = SoftwareImageFrame(image_inst_id).download_section(True, section_num, data)
+        else:
+            frame = SoftwareImageFrame(image_inst_id).download_section(False, section_num, data)
+        return self.send(frame, timeout, high_priority=high_priority)
+        
+        # if timeout > 0:
+        #     self.reactor.callLater(0, self.sim_receive_download_section_resp, 
+        #                            frame.fields["transaction_id"], 
+        #                            frame.fields["omci_message"].fields["section_number"])
+        # return d
+
+    def send_end_software_download(self, image_inst_id, crc32, image_size, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        frame = SoftwareImageFrame(image_inst_id).end_software_download(crc32, image_size)
+        return self.send(frame, timeout, high_priority=high_priority)
+        # self.reactor.callLater(0, self.sim_receive_end_software_download_resp, frame.fields["transaction_id"])
+        # return d
+
+    def send_active_image(self, image_inst_id, flag=0, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        frame = SoftwareImageFrame(image_inst_id).activate_image(flag)
+        return self.send(frame, timeout, high_priority=high_priority)
+
+    def send_commit_image(self, image_inst_id, timeout=DEFAULT_OMCI_TIMEOUT, high_priority=False):
+        frame = SoftwareImageFrame(image_inst_id).commit_image()
+        return self.send(frame, timeout, high_priority=high_priority)
+