diff --git a/python/adapters/iadapter.py b/python/adapters/iadapter.py
new file mode 100644
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+++ b/python/adapters/iadapter.py
@@ -0,0 +1,358 @@
+#
+# Copyright 2018 the original author or authors.
+#
+# 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.
+#
+
+"""
+Adapter abstract base class
+"""
+
+import structlog
+from twisted.internet import reactor
+from zope.interface import implementer
+
+from interface import IAdapterInterface
+from voltha.protos.adapter_pb2 import Adapter
+from voltha.protos.adapter_pb2 import AdapterConfig
+from voltha.protos.common_pb2 import AdminState
+from voltha.protos.common_pb2 import LogLevel
+from voltha.protos.device_pb2 import DeviceType, DeviceTypes
+from voltha.protos.health_pb2 import HealthStatus
+
+
+log = structlog.get_logger()
+
+
+@implementer(IAdapterInterface)
+class IAdapter(object):
+    def __init__(self,
+                 core_proxy,
+                 adapter_proxy,
+                 config,
+                 device_handler_class,
+                 name,
+                 vendor,
+                 version,
+                 device_type, vendor_id,
+                 accepts_bulk_flow_update=True,
+                 accepts_add_remove_flow_updates=False):
+        log.debug(
+            'Initializing adapter: {} {} {}'.format(vendor, name, version))
+        self.core_proxy = core_proxy
+        self.adapter_proxy = adapter_proxy
+        self.config = config
+        self.name = name
+        self.supported_device_types = [
+            DeviceType(
+                id=device_type,
+                vendor_id=vendor_id,
+                adapter=name,
+                accepts_bulk_flow_update=accepts_bulk_flow_update,
+                accepts_add_remove_flow_updates=accepts_add_remove_flow_updates
+            )
+        ]
+        self.descriptor = Adapter(
+            id=self.name,
+            vendor=vendor,
+            version=version,
+            config=AdapterConfig(log_level=LogLevel.INFO)
+        )
+        self.devices_handlers = dict()  # device_id -> Olt/OnuHandler()
+        self.device_handler_class = device_handler_class
+
+    def start(self):
+        log.info('Starting adapter: {}'.format(self.name))
+
+    def stop(self):
+        log.info('Stopping adapter: {}'.format(self.name))
+
+    def adapter_descriptor(self):
+        return self.descriptor
+
+    def device_types(self):
+        return DeviceTypes(items=self.supported_device_types)
+
+    def health(self):
+        # return HealthStatus(state=HealthStatus.HealthState.HEALTHY)
+        return HealthStatus(state=HealthStatus.HEALTHY)
+
+    def change_master_state(self, master):
+        raise NotImplementedError()
+
+    def get_ofp_device_info(self, device):
+        log.debug('get_ofp_device_info_start', device_id=device.id)
+        ofp_device_info = self.devices_handlers[device.id].get_ofp_device_info(
+            device)
+        log.debug('get_ofp_device_info_ends', device_id=device.id)
+        return ofp_device_info
+
+    def get_ofp_port_info(self, device, port_no):
+        log.debug('get_ofp_port_info_start', device_id=device.id,
+                  port_no=port_no)
+        ofp_port_info = self.devices_handlers[device.id].get_ofp_port_info(
+            device, port_no)
+        log.debug('get_ofp_port_info_ends', device_id=device.id,
+                  port_no=port_no)
+        return ofp_port_info
+
+    def adopt_device(self, device):
+        log.debug('adopt_device', device_id=device.id)
+        self.devices_handlers[device.id] = self.device_handler_class(self,
+                                                                     device.id)
+        reactor.callLater(0, self.devices_handlers[device.id].activate, device)
+        log.debug('adopt_device_done', device_id=device.id)
+        return device
+
+    def reconcile_device(self, device):
+        raise NotImplementedError()
+
+    def abandon_device(self, device):
+        raise NotImplementedError()
+
+    def disable_device(self, device):
+        log.info('disable-device', device_id=device.id)
+        reactor.callLater(0, self.devices_handlers[device.id].disable)
+        log.debug('disable-device-done', device_id=device.id)
+        return device
+
+    def reenable_device(self, device):
+        log.info('reenable-device', device_id=device.id)
+        reactor.callLater(0, self.devices_handlers[device.id].reenable)
+        log.info('reenable-device-done', device_id=device.id)
+        return device
+
+    def reboot_device(self, device):
+        log.info('reboot-device', device_id=device.id)
+        reactor.callLater(0, self.devices_handlers[device.id].reboot)
+        log.info('reboot-device-done', device_id=device.id)
+        return device
+
+    def download_image(self, device, request):
+        raise NotImplementedError()
+
+    def get_image_download_status(self, device, request):
+        raise NotImplementedError()
+
+    def cancel_image_download(self, device, request):
+        raise NotImplementedError()
+
+    def activate_image_update(self, device, request):
+        raise NotImplementedError()
+
+    def revert_image_update(self, device, request):
+        raise NotImplementedError()
+
+    def self_test_device(self, device):
+        log.info('self-test', device_id=device.id)
+        result = reactor.callLater(0, self.devices_handlers[
+            device.id].self_test_device)
+        log.info('self-test-done', device_id=device.id)
+        return result
+
+    def delete_device(self, device):
+        log.info('delete-device', device_id=device.id)
+        reactor.callLater(0, self.devices_handlers[device.id].delete)
+        log.info('delete-device-done', device_id=device.id)
+        return device
+
+    def get_device_details(self, device):
+        raise NotImplementedError()
+
+    def update_flows_bulk(self, device, flows, groups):
+        log.info('bulk-flow-update', device_id=device.id,
+                 flows=flows, groups=groups)
+        assert len(groups.items) == 0
+        reactor.callLater(0, self.devices_handlers[device.id].update_flow_table,
+                          flows.items)
+        return device
+
+    def update_flows_incrementally(self, device, flow_changes, group_changes):
+        log.info('incremental-flow-update', device_id=device.id,
+                 flows=flow_changes, groups=group_changes)
+        # For now, there is no support for group changes
+        assert len(group_changes.to_add.items) == 0
+        assert len(group_changes.to_remove.items) == 0
+
+        handler = self.devices_handlers[device.id]
+        # Remove flows
+        if len(flow_changes.to_remove.items) != 0:
+            reactor.callLater(0, handler.remove_from_flow_table,
+                              flow_changes.to_remove.items)
+
+        # Add flows
+        if len(flow_changes.to_add.items) != 0:
+            reactor.callLater(0, handler.add_to_flow_table,
+                              flow_changes.to_add.items)
+        return device
+
+    def update_pm_config(self, device, pm_config):
+        log.info("adapter-update-pm-config", device=device,
+                 pm_config=pm_config)
+        handler = self.devices_handlers[device.id]
+        if handler:
+            reactor.callLater(0, handler.update_pm_config, device, pm_config)
+
+    def process_inter_adapter_message(self, msg):
+        raise NotImplementedError()
+
+    def receive_packet_out(self, device_id, egress_port_no, msg):
+        raise NotImplementedError()
+
+    def suppress_alarm(self, filter):
+        raise NotImplementedError()
+
+    def unsuppress_alarm(self, filter):
+        raise NotImplementedError()
+
+    def _get_handler(self, device):
+        if device.id in self.devices_handlers:
+            handler = self.devices_handlers[device.id]
+            if handler is not None:
+                return handler
+            return None
+
+
+"""
+OLT Adapter base class
+"""
+
+
+class OltAdapter(IAdapter):
+    def __init__(self,
+                 core_proxy,
+                 adapter_proxy,
+                 config,
+                 device_handler_class,
+                 name,
+                 vendor,
+                 version, device_type,
+                 accepts_bulk_flow_update=True,
+                 accepts_add_remove_flow_updates=False):
+        super(OltAdapter, self).__init__(core_proxy=core_proxy,
+                                         adapter_proxy=adapter_proxy,
+                                         config=config,
+                                         device_handler_class=device_handler_class,
+                                         name=name,
+                                         vendor=vendor,
+                                         version=version,
+                                         device_type=device_type,
+                                         vendor_id=None,
+                                         accepts_bulk_flow_update=accepts_bulk_flow_update,
+                                         accepts_add_remove_flow_updates=accepts_add_remove_flow_updates)
+        self.logical_device_id_to_root_device_id = dict()
+
+    def reconcile_device(self, device):
+        try:
+            self.devices_handlers[device.id] = self.device_handler_class(self,
+                                                                         device.id)
+            # Work only required for devices that are in ENABLED state
+            if device.admin_state == AdminState.ENABLED:
+                reactor.callLater(0,
+                                  self.devices_handlers[device.id].reconcile,
+                                  device)
+            else:
+                # Invoke the children reconciliation which would setup the
+                # basic children data structures
+                self.core_proxy.reconcile_child_devices(device.id)
+            return device
+        except Exception, e:
+            log.exception('Exception', e=e)
+
+    def send_proxied_message(self, proxy_address, msg):
+        log.info('send-proxied-message', proxy_address=proxy_address, msg=msg)
+        handler = self.devices_handlers[proxy_address.device_id]
+        handler.send_proxied_message(proxy_address, msg)
+
+    def process_inter_adapter_message(self, msg):
+        log.debug('process-inter-adapter-message', msg=msg)
+        # Unpack the header to know which device needs to handle this message
+        handler = None
+        if msg.header.proxy_device_id:
+            # typical request
+            handler = self.devices_handlers[msg.header.proxy_device_id]
+        elif msg.header.to_device_id and \
+                msg.header.to_device_id in self.devices_handlers:
+            # typical response
+            handler = self.devices_handlers[msg.header.to_device_id]
+        if handler:
+            reactor.callLater(0, handler.process_inter_adapter_message, msg)
+
+    def receive_packet_out(self, device_id, egress_port_no, msg):
+        try:
+            log.info('receive_packet_out', device_id=device_id,
+                     egress_port=egress_port_no, msg=msg)
+            handler = self.devices_handlers[device_id]
+            if handler:
+                reactor.callLater(0, handler.packet_out, egress_port_no, msg.data)
+        except Exception, e:
+            log.exception('packet-out-failure', e=e)
+
+
+"""
+ONU Adapter base class
+"""
+
+
+class OnuAdapter(IAdapter):
+    def __init__(self,
+                 core_proxy,
+                 adapter_proxy,
+                 config,
+                 device_handler_class,
+                 name,
+                 vendor,
+                 version,
+                 device_type,
+                 vendor_id,
+                 accepts_bulk_flow_update=True,
+                 accepts_add_remove_flow_updates=False):
+        super(OnuAdapter, self).__init__(core_proxy=core_proxy,
+                                         adapter_proxy=adapter_proxy,
+                                         config=config,
+                                         device_handler_class=device_handler_class,
+                                         name=name,
+                                         vendor=vendor,
+                                         version=version,
+                                         device_type=device_type,
+                                         vendor_id=vendor_id,
+                                         accepts_bulk_flow_update=accepts_bulk_flow_update,
+                                         accepts_add_remove_flow_updates=accepts_add_remove_flow_updates)
+
+    def reconcile_device(self, device):
+        self.devices_handlers[device.id] = self.device_handler_class(self,
+                                                                     device.id)
+        # Reconcile only if state was ENABLED
+        if device.admin_state == AdminState.ENABLED:
+            reactor.callLater(0,
+                              self.devices_handlers[device.id].reconcile,
+                              device)
+        return device
+
+    def receive_proxied_message(self, proxy_address, msg):
+        log.info('receive-proxied-message', proxy_address=proxy_address,
+                 device_id=proxy_address.device_id, msg=msg)
+        # Device_id from the proxy_address is the olt device id. We need to
+        # get the onu device id using the port number in the proxy_address
+        device = self.core_proxy. \
+            get_child_device_with_proxy_address(proxy_address)
+        if device:
+            handler = self.devices_handlers[device.id]
+            handler.receive_message(msg)
+
+    def process_inter_adapter_message(self, msg):
+        log.info('process-inter-adapter-message', msg=msg)
+        # Unpack the header to know which device needs to handle this message
+        if msg.header:
+            handler = self.devices_handlers[msg.header.to_device_id]
+            handler.process_inter_adapter_message(msg)