diff --git a/__init__.py b/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/__init__.py
diff --git a/omci.py b/omci.py
new file mode 100644
index 0000000..5a94146
--- /dev/null
+++ b/omci.py
@@ -0,0 +1,23 @@
+#
+# Copyright 2017 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.
+#
+
+"""
+Omci message generator and parser implementation using scapy
+"""
+
+from omci_frame import OmciFrame
+from omci_messages import *
+from omci_entities import *
diff --git a/omci_defs.py b/omci_defs.py
new file mode 100644
index 0000000..7508411
--- /dev/null
+++ b/omci_defs.py
@@ -0,0 +1,100 @@
+#
+# Copyright 2017 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.
+#
+from enum import Enum
+from scapy.fields import PadField
+from scapy.packet import Raw
+
+
+class OmciUninitializedFieldError(Exception): pass
+
+
+class FixedLenField(PadField):
+    """
+    This Pad field limits parsing of its content to its size
+    """
+    def __init__(self, fld, align, padwith='\x00'):
+        super(FixedLenField, self).__init__(fld, align, padwith)
+
+    def getfield(self, pkt, s):
+        remain, val = self._fld.getfield(pkt, s[:self._align])
+        if isinstance(val.payload, Raw) and \
+                not val.payload.load.replace(self._padwith, ''):
+            # raw payload is just padding
+            val.remove_payload()
+        return remain + s[self._align:], val
+
+
+def bitpos_from_mask(mask, lsb_pos=0, increment=1):
+    """
+    Turn a decimal value (bitmask) into a list of indices where each
+    index value corresponds to the bit position of a bit that was set (1)
+    in the mask. What numbers are assigned to the bit positions is controlled
+    by lsb_pos and increment, as explained below.
+    :param mask: a decimal value used as a bit mask
+    :param lsb_pos: The decimal value associated with the LSB bit
+    :param increment: If this is +i, then the bit next to LSB will take
+    the decimal value of lsb_pos + i.
+    :return: List of bit positions where the bit was set in mask
+    """
+    out = []
+    while mask:
+        if mask & 0x01:
+            out.append(lsb_pos)
+        lsb_pos += increment
+        mask >>= 1
+    return sorted(out)
+
+
+class AttributeAccess(Enum):
+    Readable = 1
+    R = 1
+    Writable = 2
+    W = 2
+    SetByCreate = 3
+    SBC = 3
+
+
+OmciNullPointer = 0xffff
+
+
+class EntityOperations(Enum):
+    # keep these numbers match msg_type field per OMCI spec
+    Create = 4
+    CreateComplete = 5
+    Delete = 6
+    Set = 8
+    Get = 9
+    GetComplete = 10
+    GetAllAlarms = 11
+    GetAllAlarmsNext = 12
+    MibUpload = 13
+    MibUploadNext = 14
+    MibReset = 15
+    AlarmNotification = 16
+    AttributeValueChange = 17
+    Test = 18
+    StartSoftwareDownload = 19
+    DownlaodSection = 20
+    EndSoftwareDownload = 21
+    ActivateSoftware = 22
+    CommitSoftware = 23
+    SynchronizeTime = 24
+    Reboot = 25
+    GetNext = 26
+    TestResult = 27
+    GetCurrentData = 28
+
+
diff --git a/omci_entities.py b/omci_entities.py
new file mode 100644
index 0000000..c5afd81
--- /dev/null
+++ b/omci_entities.py
@@ -0,0 +1,812 @@
+#
+# Copyright 2017 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.
+#
+import inspect
+
+import sys
+from binascii import hexlify
+from scapy.fields import ByteField, ShortField, MACField, BitField, IPField
+from scapy.fields import IntField, StrFixedLenField
+from scapy.packet import Packet
+
+from voltha.extensions.omci.omci_defs import OmciUninitializedFieldError, \
+    AttributeAccess, OmciNullPointer, EntityOperations
+from voltha.extensions.omci.omci_defs import bitpos_from_mask
+
+
+class EntityClassAttribute(object):
+
+    def __init__(self, fld, access=set(), optional=False):
+        self._fld = fld
+        self._access = access
+        self._optional = optional
+
+
+class EntityClassMeta(type):
+    """
+    Metaclass for EntityClass to generate secondary class attributes
+    for class attributes of the derived classes.
+    """
+    def __init__(cls, name, bases, dct):
+        super(EntityClassMeta, cls).__init__(name, bases, dct)
+
+        # initialize attribute_name_to_index_map
+        cls.attribute_name_to_index_map = dict(
+            (a._fld.name, idx) for idx, a in enumerate(cls.attributes))
+
+
+class EntityClass(object):
+
+    class_id = 'to be filled by subclass'
+    attributes = []
+    mandatory_operations = {}
+    optional_operations = {}
+
+    # will be map of attr_name -> index in attributes, initialized by metaclass
+    attribute_name_to_index_map = None
+    __metaclass__ = EntityClassMeta
+
+    def __init__(self, **kw):
+        assert(isinstance(kw, dict))
+        for k, v in kw.iteritems():
+            assert(k in self.attribute_name_to_index_map)
+        self._data = kw
+
+    def serialize(self, mask=None, operation=None):
+        bytes = ''
+
+        # generate ordered list of attribute indices needed to be processed
+        # if mask is provided, we use that explicitly
+        # if mask is not provided, we determine attributes from the self._data
+        # content also taking into account the type of operation in hand
+        if mask is not None:
+            attribute_indices = EntityClass.attribute_indices_from_mask(mask)
+        else:
+            attribute_indices = self.attribute_indices_from_data()
+
+        # Serialize each indexed field (ignoring entity id)
+        for index in attribute_indices:
+            field = self.attributes[index]._fld
+            try:
+                value = self._data[field.name]
+            except KeyError:
+                raise OmciUninitializedFieldError(
+                    'Entity field "{}" not set'.format(field.name) )
+            bytes = field.addfield(None, bytes, value)
+
+        return bytes
+
+    def attribute_indices_from_data(self):
+        return sorted(
+            self.attribute_name_to_index_map[attr_name]
+            for attr_name in self._data.iterkeys())
+
+    byte1_mask_to_attr_indices = dict(
+        (m, bitpos_from_mask(m, 8, -1)) for m in range(256))
+    byte2_mask_to_attr_indices = dict(
+        (m, bitpos_from_mask(m, 16, -1)) for m in range(256))
+    @classmethod
+    def attribute_indices_from_mask(cls, mask):
+        # each bit in the 2-byte field denote an attribute index; we use a
+        # lookup table to make lookup a bit faster
+        return \
+            cls.byte1_mask_to_attr_indices[(mask >> 8) & 0xff] + \
+            cls.byte2_mask_to_attr_indices[(mask & 0xff)]
+
+    @classmethod
+    def mask_for(cls, *attr_names):
+        """
+        Return mask value corresponding to given attributes names
+        :param attr_names: Attribute names
+        :return: integer mask value
+        """
+        mask = 0
+        for attr_name in attr_names:
+            index = cls.attribute_name_to_index_map[attr_name]
+            mask |= (1 << (16 - index))
+        return mask
+
+
+# abbreviations
+ECA = EntityClassAttribute
+AA = AttributeAccess
+OP = EntityOperations
+
+
+class OntData(EntityClass):
+    class_id = 2
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ByteField("mib_data_sync", 0), {AA.R, AA.W})
+    ]
+    mandatory_operations = {OP.Get, OP.Set,
+                            OP.GetAllAlarms, OP.GetAllAlarmsNext,
+                            OP.MibReset, OP.MibUpload, OP.MibUploadNext}
+
+
+class Cardholder(EntityClass):
+    class_id = 5
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ByteField("actual_plugin_unit_type", None), {AA.R}),
+        ECA(ByteField("expected_plugin_unit_type", None), {AA.R, AA.W}),
+        ECA(ByteField("expected_port_count", None), {AA.R, AA.W},
+            optional=True),
+        ECA(StrFixedLenField("expected_equipment_id", None, 20), {AA.R, AA.W},
+            optional=True),
+        ECA(StrFixedLenField("actual_equipment_id", None, 20), {AA.R},
+            optional=True),
+        ECA(ByteField("protection_profile_pointer", None), {AA.R},
+            optional=True),
+        ECA(ByteField("invoke_protection_switch", None), {AA.R, AA.W},
+            optional=True),
+        ECA(ByteField("arc", None), {AA.R, AA.W}),
+        ECA(ByteField("arc_interval", None), {AA.R, AA.W}),
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+
+class CircuitPack(EntityClass):
+    class_id = 6
+    attributes = [
+        ECA(StrFixedLenField("managed_entity_id", None, 22), {AA.R, AA.SBC}),
+        ECA(ByteField("type", None), {AA.R, AA.SBC}),
+        ECA(ByteField("number_of_ports", None), {AA.R}, optional=True),
+        ECA(StrFixedLenField("serial_number", None, 8), {AA.R}),
+        ECA(StrFixedLenField("version", None, 14), {AA.R}),
+        ECA(StrFixedLenField("vendor_id", None, 4), {AA.R}),
+        ECA(ByteField("administrative_state", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("operational_state", None), {AA.R}, optional=True),
+        ECA(ByteField("bridged_or_ip_ind", None), {AA.R, AA.W}, optional=True),
+        ECA(StrFixedLenField("equipment_id", None, 20), {AA.R}, optional=True),
+        ECA(ByteField("card_configuration", None), {AA.R, AA.W, AA.SBC}), # not really mandatory, see spec
+        ECA(ByteField("total_tcont_buffer_number", None), {AA.R}),
+        ECA(ByteField("total_priority_queue_number", None), {AA.R}),
+        ECA(ByteField("total_traffic_scheduler_number", None), {AA.R}),
+        ECA(IntField("power_sched_override", None), {AA.R, AA.W},
+            optional=True)
+    ]
+    mandatory_operations = {OP.Get, OP.Set, OP.Reboot}
+    optional_operations = {OP.Create, OP.Delete, OP.Test}
+
+
+class SoftwareImage(EntityClass):
+    class_id = 7
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(StrFixedLenField("version", None, 14), {AA.R}),
+        ECA(ByteField("is_committed", None), {AA.R}),
+        ECA(ByteField("is_active", None), {AA.R}),
+        ECA(ByteField("is_valid", None), {AA.R}),
+    ]
+    mandatory_operations = {OP.Get}
+
+class PptpEthernetUni(EntityClass):
+    class_id = 11
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ByteField("expected_type", 0), {AA.R, AA.W}),
+        ECA(ByteField("sensed_type", 0), {AA.R}),
+        ECA(ByteField("autodetection_config", 0), {AA.R}),
+        ECA(ByteField("ethernet_loopback_config", 0), {AA.R}),
+        ECA(ByteField("administrative_state", 1), {AA.R, AA.W}),
+        ECA(ByteField("operational_state", 1), {AA.R, AA.W}),
+        ECA(ByteField("config_ind", 4), {AA.R}),
+        ECA(ByteField("max_frame_size", 1518), {AA.R, AA.W}),
+        ECA(ByteField("dte_dce_ind", 0), {AA.R, AA.W}),
+        ECA(ShortField("pause_time", 0), {AA.R, AA.W}),
+        ECA(ByteField("bridged_ip_ind", 2), {AA.R, AA.W}),
+        ECA(ByteField("arc", 0), {AA.R, AA.W}),
+        ECA(ByteField("arc_interval", 0), {AA.R, AA.W}),
+        ECA(ByteField("pppoe_filter", 0), {AA.R, AA.W}),
+        ECA(ByteField("power_control", 0), {AA.R, AA.W}),
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+class MacBridgeServiceProfile(EntityClass):
+    class_id = 45
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ByteField("spanning_tree_ind", False),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ByteField("learning_ind", False), {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ByteField("port_bridging_ind", False),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField("priority", None), {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField("max_age", None), {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField("hello_time", None), {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField("forward_delay", None), {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ByteField("unknown_mac_address_discard", False),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ByteField("mac_learning_depth", 0),
+            {AA.R, AA.W, AA.SetByCreate}, optional=True)
+
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Get, OP.Set}
+
+
+class MacBridgePortConfigurationData(EntityClass):
+    class_id = 47
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ShortField("bridge_id_pointer", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("port_num", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("tp_type", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("tp_pointer", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("port_priority", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("port_path_cost", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("port_spanning_tree_in", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("encapsulation_methods", None), {AA.R, AA.W, AA.SBC},
+            optional=True),
+        ECA(ByteField("lan_fcs_ind", None), {AA.R, AA.W, AA.SBC},
+            optional=True),
+        ECA(MACField("port_mac_address", None), {AA.R}, optional=True),
+        ECA(ShortField("outbound_td_pointer", None), {AA.R, AA.W},
+            optional=True),
+        ECA(ShortField("inbound_td_pointer", None), {AA.R, AA.W},
+            optional=True),
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Get, OP.Set}
+
+
+class VlanTaggingFilterData(EntityClass):
+    class_id = 84
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ShortField("vlan_filter_0", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_1", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_2", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_3", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_4", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_5", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_6", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_7", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_8", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_9", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_10", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("vlan_filter_11", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("forward_operation", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("number_of_entries", None), {AA.R, AA.W, AA.SBC})
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Get, OP.Set}
+
+
+class Ieee8021pMapperServiceProfile(EntityClass):
+    class_id = 130
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ShortField("tp_pointer", OmciNullPointer),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField(
+            "interwork_tp_pointer_for_p_bit_priority_0", OmciNullPointer),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField(
+            "interwork_tp_pointer_for_p_bit_priority_1", OmciNullPointer),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField(
+            "interwork_tp_pointer_for_p_bit_priority_2", OmciNullPointer),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField(
+            "interwork_tp_pointer_for_p_bit_priority_3", OmciNullPointer),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField(
+            "interwork_tp_pointer_for_p_bit_priority_4", OmciNullPointer),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField(
+            "interwork_tp_pointer_for_p_bit_priority_5", OmciNullPointer),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField(
+            "interwork_tp_pointer_for_p_bit_priority_6", OmciNullPointer),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField(
+            "interwork_tp_pointer_for_p_bit_priority_7", OmciNullPointer),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ByteField("unmarked_frame_option", None),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(StrFixedLenField("dscp_to_p_bit_mapping", None, length=24),
+            {AA.R, AA.W}),
+        ECA(ByteField("default_p_bit_marking", None),
+            {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ByteField("tp_type", None), {AA.R, AA.W, AA.SetByCreate},
+            optional=True)
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Get, OP.Set}
+
+
+class OltG(EntityClass):
+    class_id = 131
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(StrFixedLenField("olt_vendor_id", None, 4), {AA.R, AA.W}),
+        ECA(StrFixedLenField("equipment_id", None, 20), {AA.R, AA.W}),
+        ECA(StrFixedLenField("version", None, 14), {AA.R, AA.W}),
+        ECA(StrFixedLenField("time_of_day", None, 14), {AA.R, AA.W})
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+
+class OntPowerShedding(EntityClass):
+    class_id = 133
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ShortField("restore_power_time_reset_interval", None),
+            {AA.R, AA.W}),
+        ECA(ShortField("data_class_shedding_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("voice_class_shedding_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("video_overlay_class_shedding_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("video_return_class_shedding_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("dsl_class_shedding_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("atm_class_shedding_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("ces_class_shedding_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("frame_class_shedding_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("sonet_class_shedding_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("shedding_status", None), {AA.R, AA.W}),
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+
+class IpHostConfigData(EntityClass):
+    class_id = 134
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ByteField("ip_options", None), {AA.R, AA.W}),
+        ECA(MACField("mac_address", None), {AA.R}),
+        ECA(StrFixedLenField("ont_identifier", None, 25), {AA.R, AA.W}),
+        ECA(IPField("ip_address", None), {AA.R, AA.W}),
+        ECA(IPField("mask", None), {AA.R, AA.W}),
+        ECA(IPField("gateway", None), {AA.R, AA.W}),
+        ECA(IPField("primary_dns", None), {AA.R, AA.W}),
+        ECA(IPField("secondary_dns", None), {AA.R, AA.W}),
+        ECA(IPField("current_address", None), {AA.R}),
+        ECA(IPField("current_mask", None), {AA.R}),
+        ECA(IPField("current_gateway", None), {AA.R}),
+        ECA(IPField("current_primary_dns", None), {AA.R}),
+        ECA(IPField("current_secondary_dns", None), {AA.R}),
+        ECA(StrFixedLenField("domain_name", None, 25), {AA.R}),
+        ECA(StrFixedLenField("host_name", None, 25), {AA.R}),
+
+    ]
+    mandatory_operations = {OP.Get, OP.Set, OP.Test}
+
+
+class VlanTaggingOperation(Packet):
+    name = "VlanTaggingOperation"
+    fields_desc = [
+        BitField("filter_outer_priority", 0, 4),
+        BitField("filter_outer_vid", 0, 13),
+        BitField("filter_outer_tpid_de", 0, 3),
+        BitField("pad1", 0, 12),
+
+        BitField("filter_inner_priority", 0, 4),
+        BitField("filter_inner_vid", 0, 13),
+        BitField("filter_inner_tpid_de", 0, 3),
+        BitField("pad2", 0, 8),
+        BitField("filter_ether_type", 0, 4),
+
+        BitField("treatment_tags_to_remove", 0, 2),
+        BitField("pad3", 0, 10),
+        BitField("treatment_outer_priority", 0, 4),
+        BitField("treatment_outer_vid", 0, 13),
+        BitField("treatment_outer_tpid_de", 0, 3),
+
+        BitField("pad4", 0, 12),
+        BitField("treatment_inner_priority", 0, 4),
+        BitField("treatment_inner_vid", 0, 13),
+        BitField("treatment_inner_tpid_de", 0, 3),
+    ]
+
+
+class ExtendedVlanTaggingOperationConfigurationData(EntityClass):
+    class_id = 171
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SetByCreate}),
+        ECA(ByteField("association_type", None), {AA.R, AA.W, AA.SetByCreate}),
+        ECA(ShortField("received_vlan_tagging_operation_table_max_size", None),
+            {AA.R}),
+        ECA(ShortField("input_tpid", None), {AA.R, AA.W}),
+        ECA(ShortField("output_tpid", None), {AA.R, AA.W}),
+        ECA(ByteField("downstream_mode", None), {AA.R, AA.W}),
+        ECA(StrFixedLenField("received_frame_vlan_tagging_operation_table", VlanTaggingOperation, 16), {AA.R, AA.W}),
+        ECA(ShortField("associated_me_pointer", None), {AA.R, AA.W, AA.SBC})
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Set, OP.Get, OP.GetNext}
+
+
+class OntG(EntityClass):
+    class_id = 256
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(StrFixedLenField("vendor_id", None, 4), {AA.R}),
+        ECA(StrFixedLenField("version", None, 14), {AA.R}),
+        ECA(StrFixedLenField("serial_number", None, 8), {AA.R}),
+        ECA(ByteField("traffic_management_options", None), {AA.R}),
+        ECA(ByteField("vp_vc_cross_connection_option", None), {AA.R},
+            optional=True),
+        ECA(ByteField("administrative_state", None), {AA.R, AA.W}),
+        ECA(ByteField("operational_state", None), {AA.R}, optional=True),
+        ECA(ByteField("ont_survival_time", None), {AA.R})
+    ]
+    mandatory_operations = {
+        OP.Get, OP.Set, OP.Reboot, OP.Test, OP.SynchronizeTime}
+
+
+class Ont2G(EntityClass):
+    class_id = 257
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(StrFixedLenField("equipment_id", None, 20), {AA.R}),
+        ECA(ByteField("omcc_version", None), {AA.R}),
+        ECA(ShortField("vendor_product_code", None), {AA.R}, optional=True),
+        ECA(ByteField("security_capability", None), {AA.R}),
+        ECA(ByteField("security_mode", None), {AA.R, AA.W}),
+        ECA(ShortField("total_priority_queue_number", None), {AA.R}),
+        ECA(ByteField("total_traffic_scheduler_number", None), {AA.R}),
+        ECA(ByteField("mode", None), {AA.R}),
+        ECA(ShortField("total_gem_port_id_number", None), {AA.R}, optional=True),
+        ECA(IntField("sys_uptime", None), {AA.R}, optional=True),
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+
+class Tcont(EntityClass):
+    class_id = 262
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ShortField("alloc_id", 0x00ff), {AA.R, AA.W}),
+        ECA(ByteField("mode_indicator", 1), {AA.R}),
+        ECA(ByteField("policy", None), {AA.R, AA.W}),  # addendum makes it R/W
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+
+class AniG(EntityClass):
+    class_id = 263
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ByteField("sr_indication", None), {AA.R}),
+        ECA(ShortField("total_tcont_number", None), {AA.R}),
+        ECA(ShortField("gem_block_length", None), {AA.R, AA.W}),
+        ECA(ByteField("piggyback_dba_reporting", None), {AA.R}),
+        ECA(ByteField("whole_ont_dba_reporting", None), {AA.R}),
+        ECA(ByteField("sf_threshold", None), {AA.R, AA.W}),
+        ECA(ByteField("sd_threshold", None), {AA.R, AA.W}),
+        ECA(ByteField("arc", None), {AA.R, AA.W}),
+        ECA(ByteField("arc_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("optical_signal_level", None), {AA.R}),
+        ECA(ByteField("lower_optical_threshold", None), {AA.R, AA.W}, optional=True),
+        ECA(ByteField("upper_optical_threshold", None), {AA.R, AA.W}, optional=True),
+        ECA(ByteField("ont_response_time", None), {AA.R}, optional=True),
+        ECA(ShortField("transmit_optical_level", None), {AA.R}, optional=True),
+        ECA(ByteField("lower_transmit_power_threshold", None), {AA.R, AA.W},
+            optional=True),
+        ECA(ByteField("upper_transmit_power_threshold", None), {AA.R, AA.W},
+            optional=True),
+    ]
+    mandatory_operations = {OP.Get, OP.Set, OP.Test}
+
+
+class UniG(EntityClass):
+    class_id = 264
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ShortField("configuration_option_status", None), {AA.R, AA.W}),
+        ECA(ByteField("administrative_state", None), {AA.R, AA.W}),
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+
+class GemInterworkingTp(EntityClass):
+    class_id = 266
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SetByCreate}),
+        ECA(ShortField("gem_port_network_ctp_pointer", None),
+            {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("interworking_option", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("service_profile_pointer", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("interworking_tp_pointer", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("pptp_counter", None), {AA.R}, optional=True),
+        ECA(ByteField("operational_state", None), {AA.R}, optional=True),
+        ECA(ShortField("gal_profile_pointer", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("gal_loopback_configuration", None),
+            {AA.R, AA.W}),
+    ]
+    mandatory_operations = {}  # TODO
+
+
+class GemPortNetworkCtp(EntityClass):
+    class_id = 268
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ShortField("port_id", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("tcont_pointer", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("direction", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("traffic_management_pointer_upstream", None),
+            {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("traffic_descriptor_profile_pointer", None),
+            {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(ByteField("uni_counter", None), {AA.R}, optional=True),
+        ECA(ShortField("priority_queue_pointer_downstream", None),
+            {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("encryption_state", None), {AA.R}, optional=True),
+        ECA(ShortField("traffic_desc_profile_pointer_downstream", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(ShortField("encryption_key_ring", None), {AA.R, AA.W, AA.SBC}, optional=True)
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Get, OP.Set}
+
+
+class GalEthernetProfile(EntityClass):
+    class_id = 272
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ShortField("max_gem_payload_size", None), {AA.R, AA.W, AA.SBC}),
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Get, OP.Set}
+
+
+class PriorityQueueG(EntityClass):
+    class_id = 277
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ByteField("queue_configuration_option", None), {AA.R}),
+        ECA(ShortField("maximum_queue_size", None), {AA.R}),
+        ECA(ShortField("allocated_queue_size", None), {AA.R, AA.W}),
+        ECA(ShortField("discard_block_countter_reset_interval", None), {AA.R, AA.W}),
+        ECA(ShortField("threshold_value_for_discarded_blocks", None), {AA.R, AA.W}),
+        ECA(IntField("related_port", None), {AA.R}),
+        ECA(ShortField("traffic_scheduler_g_pointer", None), {AA.R, AA.W}),
+        ECA(ByteField("weight", None), {AA.R, AA.W}),
+        ECA(ShortField("back_pressure_operation", None), {AA.R, AA.W}),
+        ECA(IntField("back_pressure_time", None), {AA.R, AA.W}),
+        ECA(ShortField("back_pressure_occur_queue_threshold", None), {AA.R, AA.W}),
+        ECA(ShortField("back_pressure_clear_queue_threshold", None), {AA.R, AA.W}),
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+
+class TrafficSchedulerG(EntityClass):
+    class_id = 278
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ShortField("tcont_pointer", None), {AA.R}),
+        ECA(ShortField("traffic_scheduler_pointer", None), {AA.R}),
+        ECA(ByteField("policy", None), {AA.R}),
+        ECA(ByteField("priority_weight", None), {AA.R}),
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+
+class MulticastGemInterworkingTp(EntityClass):
+    class_id = 281
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ShortField("gem_port_network_ctp_pointer", None), {AA.R, AA.SBC}),
+        ECA(ByteField("interworking_option", None), {AA.R, AA.SBC}),
+        ECA(ShortField("service_profile_pointer", None), {AA.R, AA.SBC}),
+        ECA(ShortField("interworking_tp_pointer", 0), {AA.R, AA.SBC}),
+        ECA(ByteField("pptp_counter", None), {AA.R}, optional=True),
+        ECA(ByteField("operational_state", None), {AA.R}, optional=True),
+        ECA(ShortField("gal_profile_pointer", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("gal_loopback_configuration", None),
+            {AA.R, AA.W, AA.SBC}),
+        # TODO add multicast_address_table here (page 85 of spec.)
+        # ECA(...("multicast_address_table", None), {AA.R, AA.W})
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Get, OP.GetNext, OP.Set}
+
+
+class AccessControlRow0(Packet):
+    name = "AccessControlRow0"
+    fields_desc = [
+        BitField("set_ctrl", 0, 2),
+        BitField("row_part_id", 0, 3),
+        BitField("test", 0, 1),
+        BitField("row_key", 0, 10),
+
+        ShortField("gem_port_id", None),
+        ShortField("vlan_id", None),
+        IPField("src_ip", None),
+        IPField("dst_ip_start", None),
+        IPField("dst_ip_end", None),
+        IntField("ipm_group_bw", None),
+        ShortField("reserved0", 0)
+    ]
+
+class AccessControlRow1(Packet):
+    name = "AccessControlRow1"
+    fields_desc = [
+        BitField("set_ctrl", 0, 2),
+        BitField("row_part_id", 0, 3),
+        BitField("test", 0, 1),
+        BitField("row_key", 0, 10),
+
+        StrFixedLenField("ipv6_src_addr_start_bytes", None, 12),
+        ShortField("preview_length", None),
+        ShortField("preview_repeat_time", None),
+        ShortField("preview_repeat_count", None),
+        ShortField("preview_reset_time", None),
+        ShortField("reserved1", 0)
+    ]
+
+class AccessControlRow2(Packet):
+    name = "AccessControlRow2"
+    fields_desc = [
+        BitField("set_ctrl", 0, 2),
+        BitField("row_part_id", 0, 3),
+        BitField("test", 0, 1),
+        BitField("row_key", 0, 10),
+
+        StrFixedLenField("ipv6_dst_addr_start_bytes", None, 12),
+        StrFixedLenField("reserved2", None, 10)
+    ]
+
+class DownstreamIgmpMulticastTci(Packet):
+    name = "DownstreamIgmpMulticastTci"
+    fields_desc = [
+        ByteField("ctrl_type", None),
+        ShortField("tci", None)
+    ]
+
+class MulticastOperationsProfile(EntityClass):
+    class_id = 309
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ByteField("igmp_version", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("igmp_function", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ByteField("immediate_leave", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("us_igmp_tci", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(ByteField("us_igmp_tag_ctrl", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(IntField("us_igmp_rate", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        # TODO: need to make table and add column data
+        ECA(StrFixedLenField(
+            "dynamic_access_control_list_table", None, 24), {AA.R, AA.W}),
+        # TODO: need to make table and add column data
+        ECA(StrFixedLenField(
+            "static_access_control_list_table", None, 24), {AA.R, AA.W}),
+        # TODO: need to make table and add column data
+        ECA(StrFixedLenField("lost_groups_list_table", None, 10), {AA.R}, optional=True),
+        ECA(ByteField("robustness", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(IntField("querier_ip", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(IntField("query_interval", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(IntField("querier_max_response_time", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(IntField("last_member_response_time", None), {AA.R, AA.W}, optional=True),
+        ECA(ByteField("unauthorized_join_behaviour", None), {AA.R, AA.W}, optional=True),
+        ECA(StrFixedLenField("ds_igmp_mcast_tci", None, 3), {AA.R, AA.W, AA.SBC}, optional=True)
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Set, OP.Get, OP.GetNext}
+
+class MulticastServicePackage(Packet):
+    name = "MulticastServicePackage"
+    fields_desc = [
+        BitField("set_ctrl", 0, 2),
+        BitField("reserved0", 0, 4),
+        BitField("row_key", 0, 10),
+
+        ShortField("vid_uni", None),
+        ShortField("max_simultaneous_groups", None),
+        IntField("max_multicast_bw", None),
+        ShortField("mcast_operations_profile_pointer", None),
+        StrFixedLenField("reserved1", None, 8)
+    ]
+
+class AllowedPreviewGroupsRow0(Packet):
+    name = "AllowedPreviewGroupsRow0"
+    fields_desc = [
+        BitField("set_ctrl", 0, 2),
+        BitField("row_part_id", 0, 3),
+        BitField("reserved0", 0, 1),
+        BitField("row_key", 0, 10),
+
+        StrFixedLenField("ipv6_pad", 0, 12),
+        IPField("src_ip", None),
+        ShortField("vlan_id_ani", None),
+        ShortField("vlan_id_uni", None)
+    ]
+
+class AllowedPreviewGroupsRow1(Packet):
+    name = "AllowedPreviewGroupsRow1"
+    fields_desc = [
+        BitField("set_ctrl", 0, 2),
+        BitField("row_part_id", 0, 3),
+        BitField("reserved0", 0, 1),
+        BitField("row_key", 0, 10),
+
+        StrFixedLenField("ipv6_pad", 0, 12),
+        IPField("dst_ip", None),
+        ShortField("duration", None),
+        ShortField("time_left", None)
+    ]
+
+class MulticastSubscriberConfigInfo(EntityClass):
+    class_id = 310
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R, AA.SBC}),
+        ECA(ByteField("me_type", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("mcast_operations_profile_pointer", None), {AA.R, AA.W, AA.SBC}),
+        ECA(ShortField("max_simultaneous_groups", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(IntField("max_multicast_bandwidth", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        ECA(ByteField("bandwidth_enforcement", None), {AA.R, AA.W, AA.SBC}, optional=True),
+        # TODO: need to make table and add column data
+        ECA(StrFixedLenField(
+            "multicast_service_package_table", None, 20), {AA.R, AA.W}, optional=True),
+        # TODO: need to make table and add column data
+        ECA(StrFixedLenField(
+            "allowed_preview_groups_table", None, 22), {AA.R, AA.W}, optional=True),
+    ]
+    mandatory_operations = {OP.Create, OP.Delete, OP.Set, OP.Get, OP.GetNext}
+
+
+class VirtualEthernetInterfacePt(EntityClass):
+    class_id = 329
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(ByteField("administrative_state", None), {AA.R, AA.W}),
+        ECA(ByteField("operational_state", None), {AA.R}, optional=True),
+        ECA(StrFixedLenField(
+            "interdomain_name", None, 25), {AA.R, AA.W}, optional=True),
+        ECA(ShortField("tcp_udp_pointer", None), {AA.R, AA.W}, optional=True),
+        ECA(ShortField("iana_assigned_port", None), {AA.R}),
+    ]
+    mandatory_operations = {OP.Get, OP.Set}
+
+
+class EnhSecurityControl:
+    class_id = 332
+    attributes = [
+        ECA(ShortField("managed_entity_id", None), {AA.R}),
+        ECA(StrFixedLenField(
+            "olt_crypto_capabilities", None, 16), {AA.W}),
+        # TODO: need to make table and add column data
+        ECA(StrFixedLenField(
+            "olt_random_challenge_table", None, 17), {AA.R, AA.W}),
+        ECA(ByteField("olt_challenge_status", None), {AA.R, AA.W}),
+        ECA(ByteField("onu_selected_crypto_capabilities", None), {AA.R}),
+        # TODO: need to make table and add column data
+        ECA(StrFixedLenField(
+            "onu_random_challenge_table", None, 16), {AA.R}),
+        # TODO: need to make table and add column data
+        ECA(StrFixedLenField(
+            "onu_authentication_result_table", None, 16), {AA.R}),
+        # TODO: need to make table and add column data
+        ECA(StrFixedLenField(
+            "olt_authentication_result_table", None, 17), {AA.W}),
+        ECA(ByteField("olt_result_status", None), {AA.R, AA.W}),
+        ECA(ByteField("onu_authentication_status", None), {AA.R}),
+        ECA(StrFixedLenField(
+            "master_session_key_name", None, 16), {AA.R}),
+        ECA(StrFixedLenField(
+            "broadcast_key_table", None, 18), {AA.R, AA.W}, optional=True),
+        ECA(ShortField("effective_key_length", None), {AA.R}, optional=True),
+
+    ]
+    mandatory_operations = {OP.Set, OP.Get, OP.GetNext}
+
+
+class Unknown347(EntityClass):
+    class_id = 347
+    attributes = [
+
+    ]
+
+
+# entity class lookup table from entity_class values
+entity_classes_name_map = dict(
+    inspect.getmembers(sys.modules[__name__],
+    lambda o: inspect.isclass(o) and \
+              issubclass(o, EntityClass) and \
+              o is not EntityClass)
+)
+
+entity_classes = [c for c in entity_classes_name_map.itervalues()]
+entity_id_to_class_map = dict((c.class_id, c) for c in entity_classes)
diff --git a/omci_frame.py b/omci_frame.py
new file mode 100644
index 0000000..edff530
--- /dev/null
+++ b/omci_frame.py
@@ -0,0 +1,124 @@
+#
+# Copyright 2017 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.
+#
+from scapy.fields import ByteField, PacketField, IntField
+from scapy.fields import ShortField, ConditionalField
+from scapy.packet import Packet
+
+from voltha.extensions.omci.omci_defs import FixedLenField
+from voltha.extensions.omci.omci_messages import OmciCreate, OmciDelete, \
+    OmciDeleteResponse, OmciSet, OmciSetResponse, OmciGet, OmciGetResponse, \
+    OmciGetAllAlarms, OmciGetAllAlarmsResponse, OmciGetAllAlarmsNext, \
+    OmciMibResetResponse, OmciMibReset, OmciMibUploadNextResponse, \
+    OmciMibUploadNext, OmciMibUploadResponse, OmciMibUpload, \
+    OmciGetAllAlarmsNextResponse
+from voltha.extensions.omci.omci_messages import OmciCreateResponse
+
+
+class OmciFrame(Packet):
+    name = "OmciFrame"
+    fields_desc = [
+        ShortField("transaction_id", 0),
+        ByteField("message_type", None),
+        ByteField("omci", 0x0a),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciCreate), align=36),
+            lambda pkt: pkt.message_type == OmciCreate.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciCreateResponse), align=36),
+            lambda pkt: pkt.message_type == OmciCreateResponse.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciDelete), align=36),
+            lambda pkt: pkt.message_type == OmciDelete.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciDeleteResponse), align=36),
+            lambda pkt: pkt.message_type == OmciDeleteResponse.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciSet), align=36),
+            lambda pkt: pkt.message_type == OmciSet.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciSetResponse), align=36),
+            lambda pkt: pkt.message_type == OmciSetResponse.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciGet), align=36),
+            lambda pkt: pkt.message_type == OmciGet.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciGetResponse), align=36),
+            lambda pkt: pkt.message_type == OmciGetResponse.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciGetAllAlarms), align=36),
+            lambda pkt: pkt.message_type == OmciGetAllAlarms.message_id),
+        ConditionalField(FixedLenField(
+            PacketField(
+                "omci_message", None, OmciGetAllAlarmsResponse), align=36),
+                lambda pkt:
+                pkt.message_type == OmciGetAllAlarmsResponse.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciGetAllAlarmsNext), align=36),
+            lambda pkt: pkt.message_type == OmciGetAllAlarmsNext.message_id),
+        ConditionalField(FixedLenField(
+            PacketField(
+                "omci_message", None, OmciGetAllAlarmsNextResponse), align=36),
+                lambda pkt:
+                pkt.message_type == OmciGetAllAlarmsNextResponse.message_id),
+
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciMibUpload), align=36),
+            lambda pkt: pkt.message_type == OmciMibUpload.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciMibUploadResponse), align=36),
+            lambda pkt: pkt.message_type == OmciMibUploadResponse.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciMibUploadNext), align=36),
+            lambda pkt:
+                pkt.message_type == OmciMibUploadNext.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciMibUploadNextResponse), align=36),
+            lambda pkt: pkt.message_type == OmciMibUploadNextResponse.message_id),
+
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciMibReset), align=36),
+            lambda pkt: pkt.message_type == OmciMibReset.message_id),
+        ConditionalField(FixedLenField(
+            PacketField("omci_message", None, OmciMibResetResponse), align=36),
+            lambda pkt: pkt.message_type == OmciMibResetResponse.message_id),
+
+        # TODO add entries for remaining OMCI message types
+
+        IntField("omci_trailer", 0x00000028)
+    ]
+
+    # We needed to patch the do_dissect(...) method of Packet, because
+    # it wiped out already dissected conditional fields with None if they
+    # referred to the same field name. We marked the only new line of code
+    # with "Extra condition added".
+    def do_dissect(self, s):
+        raw = s
+        self.raw_packet_cache_fields = {}
+        for f in self.fields_desc:
+            if not s:
+                break
+            s, fval = f.getfield(self, s)
+            # We need to track fields with mutable values to discard
+            # .raw_packet_cache when needed.
+            if f.islist or f.holds_packets:
+                self.raw_packet_cache_fields[f.name] = f.do_copy(fval)
+            # Extra condition added
+            if fval is not None or f.name not in self.fields:
+                self.fields[f.name] = fval
+        assert(raw.endswith(s))
+        self.raw_packet_cache = raw[:-len(s)] if s else raw
+        self.explicit = 1
+        return s
diff --git a/omci_messages.py b/omci_messages.py
new file mode 100644
index 0000000..90a0cea
--- /dev/null
+++ b/omci_messages.py
@@ -0,0 +1,300 @@
+#
+# Copyright 2017 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.
+#
+import structlog
+from enum import Enum
+from scapy.fields import ByteField, StrFixedLenField, ConditionalField, Field
+from scapy.fields import ShortField
+from scapy.packet import Packet
+
+from voltha.extensions.omci.omci_defs import AttributeAccess
+from voltha.extensions.omci.omci_entities import entity_id_to_class_map
+
+
+log = structlog.get_logger()
+
+
+class OmciData(Field):
+
+    __slots__ = Field.__slots__ + ['_entity_class']
+
+    def __init__(self, name, entity_class="entity_class"):
+        Field.__init__(self, name=name, default=None, fmt='s')
+        self._entity_class = entity_class
+
+    def addfield(self, pkt, s, val):
+        class_id = getattr(pkt, self._entity_class)
+        entity_class = entity_id_to_class_map.get(class_id)
+        for attribute in entity_class.attributes:
+            if AttributeAccess.SetByCreate not in attribute._access:
+                continue
+            if attribute._fld.name == 'managed_entity_id':
+                continue
+            fld = attribute._fld
+            s = fld.addfield(pkt, s, val.get(fld.name, fld.default))
+        return s
+
+    def getfield(self, pkt, s):
+        """Extract an internal value from a string"""
+        class_id = getattr(pkt, self._entity_class)
+        entity_class = entity_id_to_class_map.get(class_id)
+        data = {}
+        for attribute in entity_class.attributes:
+            if AttributeAccess.SetByCreate not in attribute._access:
+                continue
+            if attribute._fld.name == 'managed_entity_id':
+                continue
+            fld = attribute._fld
+            s, value = fld.getfield(pkt, s)
+            data[fld.name] = value
+        return s, data
+
+
+class OmciMaskedData(Field):
+
+    __slots__ = Field.__slots__ + ['_entity_class', '_attributes_mask']
+
+    def __init__(self, name, entity_class="entity_class",
+                 attributes_mask="attributes_mask"):
+        Field.__init__(self, name=name, default=None, fmt='s')
+        self._entity_class = entity_class
+        self._attributes_mask = attributes_mask
+
+    def addfield(self, pkt, s, val):
+        class_id = getattr(pkt, self._entity_class)
+        attribute_mask = getattr(pkt, self._attributes_mask)
+        entity_class = entity_id_to_class_map.get(class_id)
+        indices = entity_class.attribute_indices_from_mask(attribute_mask)
+        for index in indices:
+            fld = entity_class.attributes[index]._fld
+            s = fld.addfield(pkt, s, val[fld.name])
+        return s
+
+    def getfield(self, pkt, s):
+        """Extract an internal value from a string"""
+        class_id = getattr(pkt, self._entity_class)
+        attribute_mask = getattr(pkt, self._attributes_mask)
+        entity_class = entity_id_to_class_map[class_id]
+        indices = entity_class.attribute_indices_from_mask(attribute_mask)
+        data = {}
+        for index in indices:
+            try:
+                fld = entity_class.attributes[index]._fld
+            except IndexError, e:
+                log.error("Cannot decode attribute {} for entity class {}".format(
+                        index, entity_class))
+                continue
+            try:
+                s, value = fld.getfield(pkt, s)
+            except Exception, e:
+                raise
+            data[fld.name] = value
+        return  s, data
+
+
+class OmciMessage(Packet):
+    name = "OmciMessage"
+    message_id = None  # OMCI message_type value, filled by derived classes
+    fields_desc = []
+
+
+class OmciCreate(OmciMessage):
+    name = "OmciCreate"
+    message_id = 0x44
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", 0),
+        OmciData("data")
+    ]
+
+
+class OmciCreateResponse(OmciMessage):
+    name = "OmciCreateResponse"
+    message_id = 0x24
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", None),
+        ByteField("success_code", 0),
+        ShortField("parameter_error_attributes_mask", None),
+    ]
+
+
+class OmciDelete(OmciMessage):
+    name = "OmciDelete"
+    message_id = 0x46
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", None),
+    ]
+
+
+class OmciDeleteResponse(OmciMessage):
+    name = "OmciDeleteResponse"
+    message_id = 0x26
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", None),
+        ByteField("success_code", 0),
+    ]
+
+
+class OmciSet(OmciMessage):
+    name = "OmciSet"
+    message_id = 0x48
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", 0),
+        ShortField("attributes_mask", None),
+        OmciMaskedData("data")
+    ]
+
+
+class OmciSetResponse(OmciMessage):
+    name = "OmciSetResponse"
+    message_id = 0x28
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", None),
+        ByteField("success_code", 0),
+        ShortField("unsupported_attributes_mask", None),
+        ShortField("failed_attributes_mask", None),
+    ]
+
+
+class OmciGet(OmciMessage):
+    name = "OmciGet"
+    message_id = 0x49
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", 0),
+        ShortField("attributes_mask", None)
+    ]
+
+
+class OmciGetResponse(OmciMessage):
+    name = "OmciGetResponse"
+    message_id = 0x29
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", 0),
+        ByteField("success_code", 0),
+        ShortField("attributes_mask", None),
+        ConditionalField(
+            OmciMaskedData("data"), lambda pkt: pkt.success_code == 0)
+    ]
+
+
+class OmciGetAllAlarms(OmciMessage):
+    name = "OmciGetAllAlarms"
+    message_id = 0x4b
+    fields_desc = [
+        ShortField("entity_class", 2),  # Always 2 (ONT data)
+        ShortField("entity_id", 0),  # Always 0 (ONT instance)
+        ByteField("alarm_retrieval_mode", 0)  # 0 or 1
+    ]
+
+
+class OmciGetAllAlarmsResponse(OmciMessage):
+    name = "OmciGetAllAlarmsResponse"
+    message_id = 0x2b
+    fields_desc = [
+        ShortField("entity_class", 2),  # Always 2 (ONT data)
+        ShortField("entity_id", 0),
+        ShortField("number_of_commands", None)
+    ]
+
+
+class OmciGetAllAlarmsNext(OmciMessage):
+    name = "OmciGetAllAlarmsNext"
+    message_id = 0x4c
+    fields_desc = [
+        ShortField("entity_class", 2),  # Always 2 (ONT data)
+        ShortField("entity_id", 0),
+        ShortField("command_sequence_number", None)
+    ]
+
+
+class OmciGetAllAlarmsNextResponse(OmciMessage):
+    name = "OmciGetAllAlarmsNextResponse"
+    message_id = 0x2c
+    fields_desc = [
+        ShortField("entity_class", 2),  # Always 2 (ONT data)
+        ShortField("entity_id", 0),
+        ShortField("alarmed_entity_class", None),
+        ShortField("alarmed_entity_id", 0),
+        StrFixedLenField("alarm_bit_map", None, 27)  # TODO better type?
+    ]
+
+
+class OmciMibUpload(OmciMessage):
+    name = "OmciMibUpload"
+    message_id = 0x4d
+    fields_desc = [
+        ShortField("entity_class", 2),  # Always 2 (ONT data)
+        ShortField("entity_id", 0),
+    ]
+
+
+class OmciMibUploadResponse(OmciMessage):
+    name = "OmciMibUploadResponse"
+    message_id = 0x2d
+    fields_desc = [
+        ShortField("entity_class", 2),  # Always 2 (ONT data)
+        ShortField("entity_id", 0),
+        ShortField("number_of_commands", None)
+    ]
+
+
+class OmciMibUploadNext(OmciMessage):
+    name = "OmciMibUploadNext"
+    message_id = 0x4e
+    fields_desc = [
+        ShortField("entity_class", 2),  # Always 2 (ONT data)
+        ShortField("entity_id", 0),
+        ShortField("command_sequence_number", None)
+    ]
+
+
+class OmciMibUploadNextResponse(OmciMessage):
+    name = "OmciMibUploadNextResponse"
+    message_id = 0x2e
+    fields_desc = [
+        ShortField("entity_class", 2),  # Always 2 (ONT data)
+        ShortField("entity_id", 0),
+        ShortField("object_entity_class", None),
+        ShortField("object_entity_id", 0),
+        ShortField("object_attributes_mask", None),
+        OmciMaskedData("object_data", entity_class='object_entity_class',
+                       attributes_mask='object_attributes_mask')
+    ]
+
+
+class OmciMibReset(OmciMessage):
+    name = "OmciMibReset"
+    message_id = 0x4f
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", 0)
+    ]
+
+
+class OmciMibResetResponse(OmciMessage):
+    name = "OmciMibResetResponse"
+    message_id = 0x2f
+    fields_desc = [
+        ShortField("entity_class", None),
+        ShortField("entity_id", 0),
+        ByteField("success_code", 0)
+    ]