diff --git a/ryu/app/l4_switch.py b/ryu/app/l4_switch.py
new file mode 100644
index 000000000..0c503ac53
--- /dev/null
+++ b/ryu/app/l4_switch.py
@@ -0,0 +1,144 @@
+# Copyright (C) 2011 Nippon Telegraph and Telephone Corporation.
+#
+# 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 ryu.base import app_manager
+from ryu.controller import ofp_event
+from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER
+from ryu.controller.handler import set_ev_cls
+from ryu.ofproto import ofproto_v1_3
+from ryu.lib.packet import packet
+from ryu.lib.packet import ethernet
+from ryu.lib.packet import ether_types
+
+from ryu.lib.packet import in_proto
+from ryu.lib.packet import ipv4
+from ryu.lib.packet import icmp
+from ryu.lib.packet import tcp
+from ryu.lib.packet import udp
+
+class SimpleSwitch13(app_manager.RyuApp):
+    OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
+
+    def __init__(self, *args, **kwargs):
+        super(SimpleSwitch13, self).__init__(*args, **kwargs)
+        self.mac_to_port = {}
+
+    @set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
+    def switch_features_handler(self, ev):
+        datapath = ev.msg.datapath
+        ofproto = datapath.ofproto
+        parser = datapath.ofproto_parser
+
+        # install table-miss flow entry
+        #
+        # We specify NO BUFFER to max_len of the output action due to
+        # OVS bug. At this moment, if we specify a lesser number, e.g.,
+        # 128, OVS will send Packet-In with invalid buffer_id and
+        # truncated packet data. In that case, we cannot output packets
+        # correctly.  The bug has been fixed in OVS v2.1.0.
+        match = parser.OFPMatch()
+        actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
+                                          ofproto.OFPCML_NO_BUFFER)]
+        self.add_flow(datapath, 0, match, actions)
+
+    def add_flow(self, datapath, priority, match, actions, buffer_id=None):
+        ofproto = datapath.ofproto
+        parser = datapath.ofproto_parser
+
+        inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,
+                                             actions)]
+        if buffer_id:
+            mod = parser.OFPFlowMod(datapath=datapath, buffer_id=buffer_id,
+                                    priority=priority, match=match,
+                                    instructions=inst)
+        else:
+            mod = parser.OFPFlowMod(datapath=datapath, priority=priority,
+                                    match=match, instructions=inst)
+        datapath.send_msg(mod)
+
+    @set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
+    def _packet_in_handler(self, ev):
+        # If you hit this you might want to increase
+        # the "miss_send_length" of your switch
+        if ev.msg.msg_len < ev.msg.total_len:
+            self.logger.debug("packet truncated: only %s of %s bytes",
+                              ev.msg.msg_len, ev.msg.total_len)
+        msg = ev.msg
+        datapath = msg.datapath
+        ofproto = datapath.ofproto
+        parser = datapath.ofproto_parser
+        in_port = msg.match['in_port']
+
+        pkt = packet.Packet(msg.data)
+        eth = pkt.get_protocols(ethernet.ethernet)[0]
+
+        if eth.ethertype == ether_types.ETH_TYPE_LLDP:
+            # ignore lldp packet
+            return
+        dst = eth.dst
+        src = eth.src
+
+        dpid = datapath.id
+        self.mac_to_port.setdefault(dpid, {})
+
+        self.logger.info("packet in %s %s %s %s", dpid, src, dst, in_port)
+
+        # learn a mac address to avoid FLOOD next time.
+        self.mac_to_port[dpid][src] = in_port
+
+        if dst in self.mac_to_port[dpid]:
+            out_port = self.mac_to_port[dpid][dst]
+        else:
+            out_port = ofproto.OFPP_FLOOD
+
+        actions = [parser.OFPActionOutput(out_port)]
+
+        # install a flow to avoid packet_in next time
+        if out_port != ofproto.OFPP_FLOOD:
+
+            # check IP Protocol and create a match for IP
+            if eth.ethertype == ether_types.ETH_TYPE_IP:
+                ip = pkt.get_protocol(ipv4.ipv4)
+                srcip = ip.src
+                dstip = ip.dst
+                protocol = ip.proto
+                # if ICMP Protocol
+                if protocol == in_proto.IPPROTO_ICMP:
+                    match = parser.OFPMatch(eth_type=ether_types.ETH_TYPE_IP, ipv4_src=srcip, ipv4_dst=dstip, ip_proto=protocol)
+
+                #  if TCP Protocol
+                elif protocol == in_proto.IPPROTO_TCP:
+                    t = pkt.get_protocol(tcp.tcp)
+                    match = parser.OFPMatch(eth_type=ether_types.ETH_TYPE_IP, ipv4_src=srcip, ipv4_dst=dstip, ip_proto=protocol, tcp_src=t.src_port, tcp_dst=t.dst_port,)
+
+                #  If UDP Protocol
+                elif protocol == in_proto.IPPROTO_UDP:
+                    u = pkt.get_protocol(udp.udp)
+                    match = parser.OFPMatch(eth_type=ether_types.ETH_TYPE_IP, ipv4_src=srcip, ipv4_dst=dstip, ip_proto=protocol, udp_src=u.src_port, udp_dst=u.dst_port,)            
+
+                # verify if we have a valid buffer_id, if yes avoid to send both
+                # flow_mod & packet_out
+                if msg.buffer_id != ofproto.OFP_NO_BUFFER:
+                    self.add_flow(datapath, 1, match, actions, msg.buffer_id)
+                    return
+                else:
+                    self.add_flow(datapath, 1, match, actions)
+        data = None
+        if msg.buffer_id == ofproto.OFP_NO_BUFFER:
+            data = msg.data
+
+        out = parser.OFPPacketOut(datapath=datapath, buffer_id=msg.buffer_id,
+                                  in_port=in_port, actions=actions, data=data)
+        datapath.send_msg(out)