diff --git a/neutron/db/db_base_plugin_v2.py b/neutron/db/db_base_plugin_v2.py
index 3a48b52c4d3..e6843325a42 100644
--- a/neutron/db/db_base_plugin_v2.py
+++ b/neutron/db/db_base_plugin_v2.py
@@ -17,6 +17,7 @@ import random
 
 import netaddr
 from oslo.config import cfg
+from sqlalchemy import and_
 from sqlalchemy import event
 from sqlalchemy import orm
 from sqlalchemy.orm import exc
@@ -667,7 +668,12 @@ class NeutronDbPluginV2(neutron_plugin_base_v2.NeutronPluginBaseV2,
             return
         ports = self._model_query(
             context, models_v2.Port).filter(
-                models_v2.Port.network_id == id)
+                and_(
+                    models_v2.Port.network_id == id,
+                    models_v2.Port.device_owner !=
+                    constants.DEVICE_OWNER_ROUTER_GW,
+                    models_v2.Port.device_owner !=
+                    constants.DEVICE_OWNER_FLOATINGIP))
         subnets = self._model_query(
             context, models_v2.Subnet).filter(
                 models_v2.Subnet.network_id == id)
diff --git a/neutron/tests/unit/test_db_plugin_level.py b/neutron/tests/unit/test_db_plugin_level.py
new file mode 100644
index 00000000000..3fe2be1fa22
--- /dev/null
+++ b/neutron/tests/unit/test_db_plugin_level.py
@@ -0,0 +1,83 @@
+# Copyright (c) 2014 Red Hat, Inc.
+# All Rights Reserved.
+#
+#    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 neutron.api.v2 import attributes
+from neutron.common import constants
+from neutron.common import exceptions as n_exc
+from neutron import context
+from neutron import manager
+from neutron.tests import base
+from neutron.tests.unit import test_db_plugin
+from neutron.tests.unit import testlib_api
+
+
+class TestNetworks(base.BaseTestCase):
+    def setUp(self):
+        super(TestNetworks, self).setUp()
+        self._tenant_id = 'test-tenant'
+
+        # Update the plugin
+        self.setup_coreplugin(test_db_plugin.DB_PLUGIN_KLASS)
+
+    def _create_network(self, plugin, ctx, shared=True):
+        network = {'network': {'name': 'net',
+                               'shared': shared,
+                               'admin_state_up': True,
+                               'tenant_id': self._tenant_id}}
+        created_network = plugin.create_network(ctx, network)
+        return (network, created_network['id'])
+
+    def _create_port(self, plugin, ctx, net_id, device_owner, tenant_id):
+        port = {'port': {'name': 'port',
+                         'network_id': net_id,
+                         'mac_address': attributes.ATTR_NOT_SPECIFIED,
+                         'fixed_ips': attributes.ATTR_NOT_SPECIFIED,
+                         'admin_state_up': True,
+                         'device_id': 'device_id',
+                         'device_owner': device_owner,
+                         'tenant_id': tenant_id}}
+        plugin.create_port(ctx, port)
+
+    def _test_update_shared_net_used(self,
+                                     device_owner,
+                                     expected_exception=None):
+        plugin = manager.NeutronManager.get_plugin()
+        ctx = context.get_admin_context()
+        network, net_id = self._create_network(plugin, ctx)
+
+        self._create_port(plugin,
+                          ctx,
+                          net_id,
+                          device_owner,
+                          self._tenant_id + '1')
+
+        network['network']['shared'] = False
+
+        if (expected_exception):
+            with testlib_api.ExpectedException(expected_exception):
+                plugin.update_network(ctx, net_id, network)
+        else:
+            plugin.update_network(ctx, net_id, network)
+
+    def test_update_shared_net_used_fails(self):
+        self._test_update_shared_net_used('', n_exc.InvalidSharedSetting)
+
+    def test_update_shared_net_used_as_router_gateway(self):
+        self._test_update_shared_net_used(
+            constants.DEVICE_OWNER_ROUTER_GW)
+
+    def test_update_shared_net_used_by_floating_ip(self):
+        self._test_update_shared_net_used(
+            constants.DEVICE_OWNER_FLOATINGIP)