diff --git a/ryu/controller/tunnels.py b/ryu/controller/tunnels.py
new file mode 100644
index 00000000..e322d3ae
--- /dev/null
+++ b/ryu/controller/tunnels.py
@@ -0,0 +1,204 @@
+# Copyright (C) 2012 Nippon Telegraph and Telephone Corporation.
+# Copyright (C) 2012 Isaku Yamahata <yamahata at private email ne jp>
+#
+# 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 collections
+import logging
+
+import ryu.exception as ryu_exc
+from ryu.base import app_manager
+from ryu.controller import event
+
+
+LOG = logging.getLogger(__name__)
+
+
+class RemoteDPIDAlreadyExist(ryu_exc.RyuException):
+    message = ('port (%(dpid)s, %(port)s) has already '
+               'remote dpid %(remote_dpid)s')
+
+
+class TunnelKeyAlreadyExist(ryu_exc.RyuException):
+    message = 'tunnel key %(tunnel_key)s already exists'
+
+
+class TunnelKeyNotFound(ryu_exc.RyuException):
+    message = 'no tunnel key for network %(network_id)s'
+
+
+class EventTunnelKeyBase(event.EventBase):
+    def __init__(self, network_id, tunnel_key):
+        super(EventTunnelKeyBase, self).__init__()
+        self.network_id = network_id
+        self.tunnel_key = tunnel_key
+
+
+class EventTunnelKeyAdd(EventTunnelKeyBase):
+    def __init__(self, network_id, tunnel_key):
+        super(EventTunnelKeyAdd, self).__init__(network_id, tunnel_key)
+
+
+class EventTunnelKeyDel(EventTunnelKeyBase):
+    def __init__(self, network_id, tunnel_key):
+        super(EventTunnelKeyDel, self).__init__(network_id, tunnel_key)
+
+
+class EventTunnelPort(event.EventBase):
+    def __init__(self, dpid, port_no, remote_dpid, add_del):
+        super(EventTunnelPort, self).__init__()
+        self.dpid = dpid
+        self.port_no = port_no
+        self.remote_dpid = remote_dpid
+        self.add_del = add_del
+
+
+class TunnelKeys(dict):
+    """network id(uuid) <-> tunnel key(32bit unsigned int)"""
+    def __init__(self, f):
+        super(TunnelKeys, self).__init__()
+        self.send_event = f
+
+    def get_key(self, network_id):
+        try:
+            return self[network_id]
+        except KeyError:
+            raise TunnelKeyNotFound(network_id=network_id)
+
+    def _set_key(self, network_id, tunnel_key):
+        self[network_id] = tunnel_key
+        self.send_event(EventTunnelKeyAdd(network_id, tunnel_key))
+
+    def register_key(self, network_id, tunnel_key):
+        if network_id in self:
+            raise ryu_exc.NetworkAlreadyExist(network_id=network_id)
+        if tunnel_key in self.values():
+            raise TunnelKeyAlreadyExist(tunnel_key=tunnel_key)
+        self._set_key(network_id, tunnel_key)
+
+    def update_key(self, network_id, tunnel_key):
+        if network_id not in self and tunnel_key in self.values():
+            raise TunnelKeyAlreadyExist(key=tunnel_key)
+
+        key = self.get(network_id)
+        if key is None:
+            self._set_key(network_id, tunnel_key)
+            return
+        if key != tunnel_key:
+            raise ryu_exc.NetworkAlreadyExist(network_id=network_id)
+
+    def delete_key(self, network_id):
+        try:
+            tunnel_key = self[network_id]
+            self.send_event(EventTunnelKeyDel(network_id, tunnel_key))
+            del self[network_id]
+        except KeyError:
+            raise ryu_exc.NetworkNotFound(network_id=network_id)
+
+
+class DPIDs(object):
+    """dpid -> port_no -> remote_dpid"""
+    def __init__(self, f):
+        super(DPIDs, self).__init__()
+        self.dpids = collections.defaultdict(dict)
+        self.send_event = f
+
+    def list_ports(self, dpid):
+        return self.dpids[dpid]
+
+    def _add_remote_dpid(self, dpid, port_no, remote_dpid):
+        self.dpids[dpid][port_no] = remote_dpid
+        self.send_event(EventTunnelPort(dpid, port_no, remote_dpid, True))
+
+    def add_remote_dpid(self, dpid, port_no, remote_dpid):
+        if port_no in self.dpids[dpid]:
+            raise ryu_exc.PortAlreadyExist(dpid=dpid, port=port_no,
+                                           network_id=None)
+        self._add_remote_dpid(dpid, port_no, remote_dpid)
+
+    def update_remote_dpid(self, dpid, port_no, remote_dpid):
+        remote_dpid_ = self.dpids[dpid].get(port_no)
+        if remote_dpid_ is None:
+            self._add_remote_dpid(dpid, port_no, remote_dpid)
+        elif remote_dpid_ != remote_dpid:
+            raise ryu_exc.RemoteDPIDAlreadyExist(dpid=dpid, port=port_no,
+                                                 remote_dpid=remote_dpid)
+
+    def get_remote_dpid(self, dpid, port_no):
+        try:
+            return self.dpids[dpid][port_no]
+        except KeyError:
+            raise ryu_exc.PortNotFound(dpid=dpid, port=port_no)
+
+    def delete_port(self, dpid, port_no):
+        try:
+            remote_dpid = self.dpids[dpid][port_no]
+            self.send_event(EventTunnelPort(dpid, port_no, remote_dpid, False))
+            del self.dpids[dpid][port_no]
+        except KeyError:
+            raise ryu_exc.PortNotFound(dpid=dpid, port=port_no)
+
+    def get_port(self, dpid, remote_dpid):
+        try:
+            dp = self.dpids[dpid]
+        except KeyError:
+            raise ryu_exc.PortNotFound(dpid=dpid, port=None, network_id=None)
+
+        res = [port_no for (port_no, remote_dpid_) in dp.items()
+               if remote_dpid_ == remote_dpid]
+        assert len(res) <= 1
+        if len(res) == 0:
+            raise ryu_exc.PortNotFound(dpid=dpid, port=None, network_id=None)
+        return res[0]
+
+
+class Tunnels(app_manager.RyuApp):
+    def __init__(self):
+        super(Tunnels, self).__init__()
+        self.name = 'tunnels'
+        self.tunnel_keys = TunnelKeys(self.send_event_to_observers)
+        self.dpids = DPIDs(self.send_event_to_observers)
+
+    def get_key(self, network_id):
+        return self.tunnel_keys.get_key(network_id)
+
+    def register_key(self, network_id, tunnel_key):
+        self.tunnel_keys.register_key(network_id, tunnel_key)
+
+    def update_key(self, network_id, tunnel_key):
+        self.tunnel_keys.update_key(network_id, tunnel_key)
+
+    def delete_key(self, network_id):
+        self.tunnel_keys.delete_key(network_id)
+
+    def list_ports(self, dpid):
+        return self.dpids.list_ports(dpid).keys()
+
+    def register_port(self, dpid, port_no, remote_dpid):
+        self.dpids.add_remote_dpid(dpid, port_no, remote_dpid)
+
+    def update_port(self, dpid, port_no, remote_dpid):
+        self.dpids.update_remote_dpid(dpid, port_no, remote_dpid)
+
+    def get_remote_dpid(self, dpid, port_no):
+        return self.dpids.get_remote_dpid(dpid, port_no)
+
+    def delete_port(self, dpid, port_no):
+        self.dpids.delete_port(dpid, port_no)
+
+    #
+    # methods for gre tunnel
+    #
+    def get_port(self, dpid, remote_dpid):
+        return self.dpids.get_port(dpid, remote_dpid)