diff --git a/neutron/common/exceptions.py b/neutron/common/exceptions.py
index c6ec6ccca54..373c69979b6 100644
--- a/neutron/common/exceptions.py
+++ b/neutron/common/exceptions.py
@@ -69,6 +69,10 @@ class ServiceUnavailable(NeutronException):
     message = _("The service is unavailable")
 
 
+class NotSupported(NeutronException):
+    message = _('Not supported: %(msg)s')
+
+
 class AdminRequired(NotAuthorized):
     message = _("User does not have admin privileges: %(reason)s")
 
diff --git a/neutron/db/l3_dvr_db.py b/neutron/db/l3_dvr_db.py
index f4aa8a13ea6..47fbbc63f2e 100644
--- a/neutron/db/l3_dvr_db.py
+++ b/neutron/db/l3_dvr_db.py
@@ -87,7 +87,8 @@ class L3_NAT_with_dvr_db_mixin(l3_db.L3_NAT_db_mixin,
             router_res.get('distributed') is False):
             LOG.info(_LI("Centralizing distributed router %s "
                          "is not supported"), router_db['id'])
-            raise NotImplementedError()
+            raise n_exc.NotSupported(msg=_("Migration from distributed router "
+                                           "to centralized"))
         elif (not router_db.extra_attributes.distributed and
               router_res.get('distributed')):
             # Notify advanced services of the imminent state transition
diff --git a/neutron/tests/unit/db/test_l3_dvr_db.py b/neutron/tests/unit/db/test_l3_dvr_db.py
index c5fbb45e8d7..419e168fb7a 100644
--- a/neutron/tests/unit/db/test_l3_dvr_db.py
+++ b/neutron/tests/unit/db/test_l3_dvr_db.py
@@ -85,7 +85,7 @@ class L3DvrTestCase(testlib_api.SqlTestCase):
             'distributed': True
         }
         router_db = self._create_router(router)
-        self.assertRaises(NotImplementedError,
+        self.assertRaises(exceptions.NotSupported,
                           self.mixin._validate_router_migration,
                           self.ctx, router_db, {'distributed': False})