diff --git a/ponsim/ponsim.py b/ponsim/ponsim.py
new file mode 100644
index 0000000..c855e39
--- /dev/null
+++ b/ponsim/ponsim.py
@@ -0,0 +1,236 @@
+#
+# Copyright 2016 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.
+#
+
+"""
+Simple PON Simulator which would not be needed if openvswitch could do
+802.1ad (QinQ), which it cannot (the reason is beyond me), or if CPQD could
+handle 0-tagged packets (no comment).
+"""
+import structlog
+from scapy.layers.inet import IP, UDP
+from scapy.layers.l2 import Ether, Dot1Q
+from scapy.packet import Packet
+
+from common.frameio.frameio import hexify
+from voltha.protos import third_party
+from voltha.core.flow_decomposer import *
+_ = third_party
+
+
+def ipv4int2str(ipv4int):
+    return '{}.{}.{}.{}'.format(
+        (ipv4int >> 24) & 0xff,
+        (ipv4int >> 16) & 0xff,
+        (ipv4int >> 8) & 0xff,
+        ipv4int & 0xff
+    )
+
+
+class SimDevice(object):
+
+    def __init__(self, name, logical_port_no):
+        self.name = name
+        self.logical_port_no = logical_port_no
+        self.links = dict()
+        self.flows = list()
+        self.log = structlog.get_logger(name=name,
+                                        logical_port_no=logical_port_no)
+
+    def link(self, port, egress_fun):
+        self.links.setdefault(port, []).append(egress_fun)
+
+    def ingress(self, port, frame):
+        self.log.debug('ingress', ingress_port=port)
+        outcome = self.process_frame(port, frame)
+        if outcome is not None:
+            egress_port, egress_frame = outcome
+            forwarded = 0
+            links = self.links.get(egress_port)
+            if links is not None:
+                for fun in links:
+                    forwarded += 1
+                    self.log.debug('forwarding', egress_port=egress_port)
+                    fun(egress_port, egress_frame)
+            if not forwarded:
+                self.log.debug('no-one-to-forward-to', egress_port=egress_port)
+        else:
+            self.log.debug('dropped')
+
+    def install_flows(self, flows):
+        # store flows in precedence order so we can roll down on frame arrival
+        self.flows = sorted(flows, key=lambda fm: fm.priority, reverse=True)
+
+    def process_frame(self, ingress_port, ingress_frame):
+        for flow in self.flows:
+            if self.is_match(flow, ingress_port, ingress_frame):
+                egress_port, egress_frame = self.process_actions(
+                    flow, ingress_frame)
+                return egress_port, egress_frame
+        return None
+
+    @staticmethod
+    def is_match(flow, ingress_port, frame):
+
+        def get_non_shim_ether_type(f):
+            if f.haslayer(Dot1Q):
+                f = f.getlayer(Dot1Q)
+            return f.type
+
+        def get_vlan_pcp(f):
+            if f.haslayer(Dot1Q):
+                return f.getlayer(Dot1Q).prio
+
+        def get_ip_proto(f):
+            if f.haslayer(IP):
+                return f.getlayer(IP).proto
+
+        def get_ipv4_dst(f):
+            if f.haslayer(IP):
+                return f.getlayer(IP).dst
+
+        def get_udp_dst(f):
+            if f.haslayer(UDP):
+                return f.getlayer(UDP).dport
+
+        for field in get_ofb_fields(flow):
+
+            if field.type == IN_PORT:
+                if field.port != ingress_port:
+                    return False
+
+            elif field.type == ETH_TYPE:
+                if field.eth_type != get_non_shim_ether_type(frame):
+                    return False
+
+            elif field.type == IP_PROTO:
+                if field.ip_proto != get_ip_proto(frame):
+                    return False
+
+            elif field.type == VLAN_VID:
+                expected_vlan = field.vlan_vid
+                tagged = frame.haslayer(Dot1Q)
+                if bool(expected_vlan & 4096) != bool(tagged):
+                    return False
+                if tagged:
+                    actual_vid = frame.getlayer(Dot1Q).vlan
+                    if actual_vid != expected_vlan & 4095:
+                        return False
+
+            elif field.type == VLAN_PCP:
+                if field.vlan_pcp != get_vlan_pcp(frame):
+                    return False
+
+            elif field.type == IPV4_DST:
+                if ipv4int2str(field.ipv4_dst) != get_ipv4_dst(frame):
+                    return False
+
+            elif field.type == UDP_DST:
+                if field.udsp_dst != get_udp_dst(frame):
+                    return False
+
+            else:
+                raise NotImplementedError('field.type=%d' % field.type)
+
+        return True
+
+    @staticmethod
+    def process_actions(flow, frame):
+        egress_port = None
+        for action in get_actions(flow):
+
+            if action.type == OUTPUT:
+                egress_port = action.output.port
+
+            elif action.type == POP_VLAN:
+                if frame.haslayer(Dot1Q):
+                    shim = frame.getlayer(Dot1Q)
+                    frame = Ether(
+                        src=frame.src,
+                        dst=frame.dst,
+                        type=shim.type) / shim.payload
+
+            elif action.type == PUSH_VLAN:
+                frame = (
+                    Ether(src=frame.src, dst=frame.dst,
+                          type=action.push.ethertype) /
+                    Dot1Q(type=frame.type) /
+                    frame.payload
+                )
+
+            elif action.type == SET_FIELD:
+                assert (action.set_field.field.oxm_class ==
+                        ofp.OFPXMC_OPENFLOW_BASIC)
+                field = action.set_field.field.ofb_field
+
+                if field.type == VLAN_VID:
+                    shim = frame.getlayer(Dot1Q)
+                    shim.vlan = field.vlan_vid & 4095
+
+                elif field.type == VLAN_PCP:
+                    shim = frame.getlayer(Dot1Q)
+                    shim.prio = field.vlan_pcp
+
+                else:
+                    raise NotImplementedError('set_field.field.type=%d'
+                                              % field.type)
+
+            else:
+                raise NotImplementedError('action.type=%d' % action.type)
+
+        return egress_port, frame
+
+
+class PonSim(object):
+
+    def __init__(self, onus, egress_fun):
+        self.egress_fun = egress_fun
+
+        # Create OLT and hook NNI port up for egress
+        self.olt = SimDevice('olt', 0)
+        self.olt.link(2, lambda _, frame: self.egress_fun(0, frame))
+        self.devices = dict()
+        self.devices[0] = self.olt
+
+        # Create ONUs of the requested number and hook them up with OLT
+        # and with egress fun
+        def mk_egress_fun(port_no):
+            return lambda _, frame: self.egress_fun(port_no, frame)
+
+        def mk_onu_ingress(onu):
+            return lambda _, frame: onu.ingress(1, frame)
+
+        for i in range(onus):
+            port_no = 128 + i
+            onu = SimDevice('onu%d' % i, port_no)
+            onu.link(1, lambda _, frame: self.olt.ingress(1, frame))
+            onu.link(2, mk_egress_fun(port_no))
+            self.olt.link(1, mk_onu_ingress(onu))
+            self.devices[port_no] = onu
+
+    def get_ports(self):
+        return sorted(self.devices.keys())
+
+    def olt_install_flows(self, flows):
+        self.olt.install_flows(flows)
+
+    def onu_install_flows(self, onu_port, flows):
+        self.devices[onu_port].install_flows(flows)
+
+    def ingress(self, port, frame):
+        if not isinstance(frame, Packet):
+            frame = Ether(frame)
+        self.devices[port].ingress(2, frame)
+