diff --git a/neutron/db/db_base_plugin_v2.py b/neutron/db/db_base_plugin_v2.py
index aa155048c9c..54b00b5b8c5 100644
--- a/neutron/db/db_base_plugin_v2.py
+++ b/neutron/db/db_base_plugin_v2.py
@@ -521,8 +521,7 @@ class NeutronDbPluginV2(db_base_plugin_common.DbBasePluginCommon,
             raise n_exc.BadRequest(resource='subnets', msg=reason)
 
         mode_list = [constants.IPV6_SLAAC,
-                     constants.DHCPV6_STATELESS,
-                     attributes.ATTR_NOT_SPECIFIED]
+                     constants.DHCPV6_STATELESS]
 
         ra_mode = subnet.get('ipv6_ra_mode')
         if ra_mode not in mode_list:
diff --git a/neutron/tests/unit/db/test_db_base_plugin_v2.py b/neutron/tests/unit/db/test_db_base_plugin_v2.py
index 3fea278d2db..dca298fb39d 100644
--- a/neutron/tests/unit/db/test_db_base_plugin_v2.py
+++ b/neutron/tests/unit/db/test_db_base_plugin_v2.py
@@ -3000,6 +3000,38 @@ class TestSubnetsV2(NeutronDbPluginV2TestCase):
             res = subnet_req.get_response(self.api)
             self.assertEqual(webob.exc.HTTPClientError.code, res.status_int)
 
+    def _test_create_subnet_V6_pd_modes(self, ra_addr_mode, expect_fail=False):
+        cfg.CONF.set_override('ipv6_pd_enabled', True)
+        with self.network() as network:
+            data = {'subnet': {'network_id': network['network']['id'],
+                    'ip_version': '6',
+                    'tenant_id': network['network']['tenant_id']}}
+            if ra_addr_mode:
+                data['subnet']['ipv6_ra_mode'] = ra_addr_mode
+                data['subnet']['ipv6_address_mode'] = ra_addr_mode
+            subnet_req = self.new_create_request('subnets', data)
+            res = subnet_req.get_response(self.api)
+            if expect_fail:
+                self.assertEqual(webob.exc.HTTPClientError.code,
+                                 res.status_int)
+            else:
+                subnet = self.deserialize(self.fmt, res)['subnet']
+                self.assertEqual(constants.IPV6_PD_POOL_ID,
+                                 subnet['subnetpool_id'])
+
+    def test_create_subnet_V6_pd_slaac(self):
+        self._test_create_subnet_V6_pd_modes('slaac')
+
+    def test_create_subnet_V6_pd_stateless(self):
+        self._test_create_subnet_V6_pd_modes('dhcpv6-stateless')
+
+    def test_create_subnet_V6_pd_statefull(self):
+        self._test_create_subnet_V6_pd_modes('dhcpv6-statefull',
+                                             expect_fail=True)
+
+    def test_create_subnet_V6_pd_no_mode(self):
+        self._test_create_subnet_V6_pd_modes(None, expect_fail=True)
+
     def test_create_2_subnets_overlapping_cidr_allowed_returns_200(self):
         cidr_1 = '10.0.0.0/23'
         cidr_2 = '10.0.0.0/24'