diff --git a/neutron/api/extensions.py b/neutron/api/extensions.py
index fb9c3060684..45ce6d1f0bd 100644
--- a/neutron/api/extensions.py
+++ b/neutron/api/extensions.py
@@ -30,7 +30,7 @@ import webob.exc
 
 from neutron._i18n import _, _LE, _LI, _LW
 from neutron.common import exceptions
-import neutron.extensions
+from neutron import extensions as core_extensions
 from neutron.plugins.common import constants as const
 from neutron.services import provider_configuration
 from neutron import wsgi
@@ -85,11 +85,6 @@ class PluginInterface(object):
         return True
 
 
-# Temporary redirector to prevent subprojects from breaking.
-# TODO(HenryG): Remove once all subprojects are patched.
-ExtensionDescriptor = api_extensions.ExtensionDescriptor
-
-
 class ActionExtensionController(wsgi.Controller):
 
     def __init__(self, application):
@@ -430,7 +425,7 @@ class ExtensionManager(object):
         except AttributeError:
             LOG.exception(_LE("Exception loading extension"))
             return False
-        return isinstance(extension, ExtensionDescriptor)
+        return isinstance(extension, api_extensions.ExtensionDescriptor)
 
     def _load_all_extensions(self):
         """Load extensions from the configured path.
@@ -629,7 +624,7 @@ def get_extensions_path(service_plugins=None):
     paths = collections.OrderedDict()
 
     # Add Neutron core extensions
-    paths[neutron.extensions.__path__[0]] = 1
+    paths[core_extensions.__path__[0]] = 1
     if service_plugins:
         # Add Neutron *-aas extensions
         for plugin in service_plugins.values():
diff --git a/neutron/extensions/address_scope.py b/neutron/extensions/address_scope.py
index 50ef3a770a1..84e21ef3d7f 100644
--- a/neutron/extensions/address_scope.py
+++ b/neutron/extensions/address_scope.py
@@ -15,6 +15,7 @@
 import abc
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib import constants
 from neutron_lib import exceptions as nexception
 from neutron_lib.plugins import directory
@@ -94,7 +95,7 @@ class AddressScopeUpdateError(nexception.BadRequest):
                 "%(reason)s")
 
 
-class Address_scope(extensions.ExtensionDescriptor):
+class Address_scope(api_extensions.ExtensionDescriptor):
     """Extension class supporting Address Scopes."""
 
     @classmethod
diff --git a/neutron/extensions/agent.py b/neutron/extensions/agent.py
index 5697eb63aab..8d772553aee 100644
--- a/neutron/extensions/agent.py
+++ b/neutron/extensions/agent.py
@@ -16,6 +16,7 @@
 import abc
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib import exceptions
 from neutron_lib.plugins import directory
 import six
@@ -76,7 +77,7 @@ class MultipleAgentFoundByTypeHost(exceptions.Conflict):
                 "host=%(host)s found")
 
 
-class Agent(extensions.ExtensionDescriptor):
+class Agent(api_extensions.ExtensionDescriptor):
     """Agent management extension."""
 
     @classmethod
diff --git a/neutron/extensions/allowedaddresspairs.py b/neutron/extensions/allowedaddresspairs.py
index d2170fcbd59..e1f718dffdf 100644
--- a/neutron/extensions/allowedaddresspairs.py
+++ b/neutron/extensions/allowedaddresspairs.py
@@ -13,6 +13,7 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib.api import validators
 from neutron_lib import constants
 from neutron_lib import exceptions as nexception
@@ -20,7 +21,6 @@ from oslo_config import cfg
 import webob.exc
 
 from neutron._i18n import _
-from neutron.api import extensions
 from neutron.conf.extensions import allowedaddresspairs as addr_pair
 
 addr_pair.register_allowed_address_pair_opts()
diff --git a/neutron/extensions/auto_allocated_topology.py b/neutron/extensions/auto_allocated_topology.py
index 2b533b8908b..15162cd0e73 100644
--- a/neutron/extensions/auto_allocated_topology.py
+++ b/neutron/extensions/auto_allocated_topology.py
@@ -15,6 +15,7 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib.plugins import directory
 
 from neutron.api import extensions
@@ -44,7 +45,7 @@ RESOURCE_ATTRIBUTE_MAP = {
 }
 
 
-class Auto_allocated_topology(extensions.ExtensionDescriptor):
+class Auto_allocated_topology(api_extensions.ExtensionDescriptor):
 
     @classmethod
     def get_name(cls):
diff --git a/neutron/extensions/availability_zone.py b/neutron/extensions/availability_zone.py
index 1644c7dc635..8ec6c42e87b 100644
--- a/neutron/extensions/availability_zone.py
+++ b/neutron/extensions/availability_zone.py
@@ -14,6 +14,7 @@
 
 import abc
 
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib.api import validators
 from neutron_lib import exceptions
 from neutron_lib.plugins import directory
@@ -78,7 +79,7 @@ class AvailabilityZoneNotFound(exceptions.NotFound):
     message = _("AvailabilityZone %(availability_zone)s could not be found.")
 
 
-class Availability_zone(extensions.ExtensionDescriptor):
+class Availability_zone(api_extensions.ExtensionDescriptor):
     """Availability zone extension."""
 
     @classmethod
diff --git a/neutron/extensions/default_subnetpools.py b/neutron/extensions/default_subnetpools.py
index 5b532e67388..24ae6b6beb1 100644
--- a/neutron/extensions/default_subnetpools.py
+++ b/neutron/extensions/default_subnetpools.py
@@ -12,9 +12,9 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib import constants
 
-from neutron.api import extensions
 from neutron.api.v2 import attributes
 
 
diff --git a/neutron/extensions/dhcpagentscheduler.py b/neutron/extensions/dhcpagentscheduler.py
index f53bb145b45..6fc80f54834 100644
--- a/neutron/extensions/dhcpagentscheduler.py
+++ b/neutron/extensions/dhcpagentscheduler.py
@@ -15,6 +15,7 @@
 
 import abc
 
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib import constants
 from neutron_lib import exceptions
 from neutron_lib.plugins import directory
@@ -78,7 +79,7 @@ class DhcpAgentsHostingNetworkController(wsgi.Controller):
             request.context, kwargs['network_id'])
 
 
-class Dhcpagentscheduler(extensions.ExtensionDescriptor):
+class Dhcpagentscheduler(api_extensions.ExtensionDescriptor):
     """Extension class supporting dhcp agent scheduler.
     """
 
diff --git a/neutron/extensions/dns.py b/neutron/extensions/dns.py
index b213f522888..189abdfb907 100644
--- a/neutron/extensions/dns.py
+++ b/neutron/extensions/dns.py
@@ -15,13 +15,13 @@
 
 import re
 
+from neutron_lib.api import extensions
 from neutron_lib.api import validators
 from neutron_lib import exceptions as n_exc
 from oslo_config import cfg
 import six
 
 from neutron._i18n import _
-from neutron.api import extensions
 from neutron.api.v2 import attributes as attr
 from neutron.extensions import l3
 
diff --git a/neutron/extensions/dvr.py b/neutron/extensions/dvr.py
index 61068607bfc..b05e1a4df27 100644
--- a/neutron/extensions/dvr.py
+++ b/neutron/extensions/dvr.py
@@ -15,12 +15,12 @@
 import abc
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib import constants
 from neutron_lib import exceptions
 import six
 
 from neutron._i18n import _
-from neutron.api import extensions
 
 DISTRIBUTED = 'distributed'
 EXTENDED_ATTRIBUTES_2_0 = {
diff --git a/neutron/extensions/external_net.py b/neutron/extensions/external_net.py
index a556dc88520..d4b26e050e1 100644
--- a/neutron/extensions/external_net.py
+++ b/neutron/extensions/external_net.py
@@ -14,10 +14,10 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib import exceptions as nexception
 
 from neutron._i18n import _
-from neutron.api import extensions
 
 
 class ExternalNetworkInUse(nexception.InUse):
diff --git a/neutron/extensions/extra_dhcp_opt.py b/neutron/extensions/extra_dhcp_opt.py
index d3c4602e7de..900a1a685c9 100644
--- a/neutron/extensions/extra_dhcp_opt.py
+++ b/neutron/extensions/extra_dhcp_opt.py
@@ -14,11 +14,11 @@
 # limitations under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib.api import validators
 from neutron_lib import exceptions
 
 from neutron._i18n import _
-from neutron.api import extensions
 
 
 # ExtraDHcpOpts Exceptions
diff --git a/neutron/extensions/extraroute.py b/neutron/extensions/extraroute.py
index c4eb5fe2e0b..99ba1bdd3b1 100644
--- a/neutron/extensions/extraroute.py
+++ b/neutron/extensions/extraroute.py
@@ -14,11 +14,11 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib import constants
 from neutron_lib import exceptions as nexception
 
 from neutron._i18n import _
-from neutron.api import extensions
 
 
 # Extra Routes Exceptions
diff --git a/neutron/extensions/flavors.py b/neutron/extensions/flavors.py
index 3fcaadabf43..651c3a55c90 100644
--- a/neutron/extensions/flavors.py
+++ b/neutron/extensions/flavors.py
@@ -13,6 +13,7 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib.api import validators
 from neutron_lib import exceptions as nexception
 from neutron_lib.plugins import directory
@@ -175,7 +176,7 @@ SUB_RESOURCE_ATTRIBUTE_MAP = {
 }
 
 
-class Flavors(extensions.ExtensionDescriptor):
+class Flavors(api_extensions.ExtensionDescriptor):
 
     @classmethod
     def get_name(cls):
diff --git a/neutron/extensions/ip_allocation.py b/neutron/extensions/ip_allocation.py
index b3327833e98..8e43a4d86f2 100644
--- a/neutron/extensions/ip_allocation.py
+++ b/neutron/extensions/ip_allocation.py
@@ -12,7 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from neutron.api import extensions
+from neutron_lib.api import extensions
+
 from neutron.api.v2 import attributes
 
 IP_ALLOCATION = 'ip_allocation'
diff --git a/neutron/extensions/l2_adjacency.py b/neutron/extensions/l2_adjacency.py
index b02be5444ab..795a3d94272 100644
--- a/neutron/extensions/l2_adjacency.py
+++ b/neutron/extensions/l2_adjacency.py
@@ -13,7 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from neutron.api import extensions
+from neutron_lib.api import extensions
 
 
 L2_ADJACENCY = 'l2_adjacency'
diff --git a/neutron/extensions/l3.py b/neutron/extensions/l3.py
index 693f1e7583e..167aca60a17 100644
--- a/neutron/extensions/l3.py
+++ b/neutron/extensions/l3.py
@@ -16,11 +16,11 @@
 import abc
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib import exceptions as nexception
 import six
 
 from neutron._i18n import _
-from neutron.api import extensions
 from neutron.api.v2 import attributes as attr
 from neutron.api.v2 import resource_helper
 from neutron.conf import quota
diff --git a/neutron/extensions/l3_ext_gw_mode.py b/neutron/extensions/l3_ext_gw_mode.py
index 3d7c24340aa..ac8fa94b4a0 100644
--- a/neutron/extensions/l3_ext_gw_mode.py
+++ b/neutron/extensions/l3_ext_gw_mode.py
@@ -14,8 +14,8 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 
-from neutron.api import extensions
 from neutron.extensions import l3
 
 
diff --git a/neutron/extensions/l3_ext_ha_mode.py b/neutron/extensions/l3_ext_ha_mode.py
index 58662b29c2b..0355b753d2e 100644
--- a/neutron/extensions/l3_ext_ha_mode.py
+++ b/neutron/extensions/l3_ext_ha_mode.py
@@ -13,11 +13,11 @@
 # under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib import constants
 from neutron_lib import exceptions
 
 from neutron._i18n import _
-from neutron.api import extensions
 from neutron.common import constants as n_const
 
 HA_INFO = 'ha'
diff --git a/neutron/extensions/l3_flavors.py b/neutron/extensions/l3_flavors.py
index b1f9cd6242c..3f397c579ee 100644
--- a/neutron/extensions/l3_flavors.py
+++ b/neutron/extensions/l3_flavors.py
@@ -12,9 +12,9 @@
 # under the License.
 #
 
+from neutron_lib.api import extensions
 from neutron_lib import constants
 
-from neutron.api import extensions
 
 EXTENDED_ATTRIBUTES_2_0 = {
     'routers': {
diff --git a/neutron/extensions/l3agentscheduler.py b/neutron/extensions/l3agentscheduler.py
index aae7bc55e59..8d9c4654f31 100644
--- a/neutron/extensions/l3agentscheduler.py
+++ b/neutron/extensions/l3agentscheduler.py
@@ -15,6 +15,7 @@
 
 import abc
 
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib import constants
 from neutron_lib import exceptions
 from neutron_lib.plugins import directory
@@ -102,7 +103,7 @@ class L3AgentsHostingRouterController(wsgi.Controller):
             request.context, kwargs['router_id'])
 
 
-class L3agentscheduler(extensions.ExtensionDescriptor):
+class L3agentscheduler(api_extensions.ExtensionDescriptor):
     """Extension class supporting l3 agent scheduler.
     """
 
diff --git a/neutron/extensions/metering.py b/neutron/extensions/metering.py
index 816ea1347bb..56709bcaf85 100644
--- a/neutron/extensions/metering.py
+++ b/neutron/extensions/metering.py
@@ -15,11 +15,11 @@
 import abc
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib import exceptions as nexception
 import six
 
 from neutron._i18n import _
-from neutron.api import extensions
 from neutron.api.v2 import attributes as attr
 from neutron.api.v2 import resource_helper
 from neutron.plugins.common import constants
diff --git a/neutron/extensions/multiprovidernet.py b/neutron/extensions/multiprovidernet.py
index bf510eeb802..e03270910e9 100644
--- a/neutron/extensions/multiprovidernet.py
+++ b/neutron/extensions/multiprovidernet.py
@@ -14,13 +14,13 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib.api import validators
 from neutron_lib import constants
 from neutron_lib import exceptions as nexception
 import webob.exc
 
 from neutron._i18n import _
-from neutron.api import extensions
 from neutron.extensions import providernet as pnet
 
 SEGMENTS = 'segments'
diff --git a/neutron/extensions/netmtu.py b/neutron/extensions/netmtu.py
index ce0477cb669..061b2e81e65 100644
--- a/neutron/extensions/netmtu.py
+++ b/neutron/extensions/netmtu.py
@@ -12,7 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from neutron.api import extensions
+from neutron_lib.api import extensions
 
 
 MTU = 'mtu'
diff --git a/neutron/extensions/network_availability_zone.py b/neutron/extensions/network_availability_zone.py
index 2e62efb716d..3beb0e1c9c0 100644
--- a/neutron/extensions/network_availability_zone.py
+++ b/neutron/extensions/network_availability_zone.py
@@ -14,9 +14,9 @@
 
 import abc
 
+from neutron_lib.api import extensions
 import six
 
-from neutron.api import extensions
 from neutron.extensions import availability_zone as az_ext
 
 
diff --git a/neutron/extensions/network_ip_availability.py b/neutron/extensions/network_ip_availability.py
index a39f5f0a6cb..ed798728080 100644
--- a/neutron/extensions/network_ip_availability.py
+++ b/neutron/extensions/network_ip_availability.py
@@ -13,6 +13,8 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 
+from neutron_lib.api import extensions as api_extensions
+
 import neutron.api.extensions as extensions
 import neutron.api.v2.base as base
 import neutron.services.network_ip_availability.plugin as plugin
@@ -41,7 +43,7 @@ RESOURCE_ATTRIBUTE_MAP = {
 }
 
 
-class Network_ip_availability(extensions.ExtensionDescriptor):
+class Network_ip_availability(api_extensions.ExtensionDescriptor):
     """Extension class supporting network ip availability information."""
 
     @classmethod
diff --git a/neutron/extensions/pagination.py b/neutron/extensions/pagination.py
index f535e68c486..da75aefda26 100644
--- a/neutron/extensions/pagination.py
+++ b/neutron/extensions/pagination.py
@@ -11,13 +11,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from neutron_lib.api import extensions as api_extensions
+
 from neutron.api import extensions
 
 
 _ALIAS = 'pagination'
 
 
-class Pagination(extensions.ExtensionDescriptor):
+class Pagination(api_extensions.ExtensionDescriptor):
     """Fake extension that indicates that pagination is enabled."""
 
     extensions.register_custom_supported_check(
diff --git a/neutron/extensions/portbindings.py b/neutron/extensions/portbindings.py
index 1070e5bb580..00cfe129a70 100644
--- a/neutron/extensions/portbindings.py
+++ b/neutron/extensions/portbindings.py
@@ -13,9 +13,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from neutron_lib.api import extensions
 from neutron_lib import constants
 
-from neutron.api import extensions
 
 # The type of vnic that this port should be attached to
 VNIC_TYPE = 'binding:vnic_type'
diff --git a/neutron/extensions/portsecurity.py b/neutron/extensions/portsecurity.py
index a5ec20b998d..96ea1e4756f 100644
--- a/neutron/extensions/portsecurity.py
+++ b/neutron/extensions/portsecurity.py
@@ -13,11 +13,11 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib import constants
 from neutron_lib import exceptions as nexception
 
 from neutron._i18n import _
-from neutron.api import extensions
 
 
 DEFAULT_PORT_SECURITY = True
diff --git a/neutron/extensions/project_id.py b/neutron/extensions/project_id.py
index 678bfa94416..1e8bad09cf1 100644
--- a/neutron/extensions/project_id.py
+++ b/neutron/extensions/project_id.py
@@ -11,13 +11,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from neutron_lib.api import extensions as api_extensions
+
 from neutron.api import extensions
 
 
 _ALIAS = 'project-id'
 
 
-class Project_id(extensions.ExtensionDescriptor):
+class Project_id(api_extensions.ExtensionDescriptor):
     """Extension that indicates that project_id is enabled.
 
     This extension indicates that the Keystone V3 'project_id' field
diff --git a/neutron/extensions/providernet.py b/neutron/extensions/providernet.py
index 1bf98af823e..5d440f35269 100644
--- a/neutron/extensions/providernet.py
+++ b/neutron/extensions/providernet.py
@@ -14,12 +14,12 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib.api import validators
 from neutron_lib import constants
 from neutron_lib import exceptions as n_exc
 
 from neutron._i18n import _
-from neutron.api import extensions
 
 
 NETWORK_TYPE = 'provider:network_type'
diff --git a/neutron/extensions/qos.py b/neutron/extensions/qos.py
index 201413c54bd..2bd0fcb9d7f 100644
--- a/neutron/extensions/qos.py
+++ b/neutron/extensions/qos.py
@@ -18,6 +18,7 @@ import itertools
 import re
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib.plugins import directory
 import six
 
@@ -130,7 +131,7 @@ EXTENDED_ATTRIBUTES_2_0 = {
                                     'validate': {'type:uuid_or_none': None}}}}
 
 
-class Qos(extensions.ExtensionDescriptor):
+class Qos(api_extensions.ExtensionDescriptor):
     """Quality of Service API extension."""
 
     @classmethod
diff --git a/neutron/extensions/quotasv2.py b/neutron/extensions/quotasv2.py
index 7c7f991b1f0..2a9b49e3ccc 100644
--- a/neutron/extensions/quotasv2.py
+++ b/neutron/extensions/quotasv2.py
@@ -14,6 +14,7 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib import exceptions as n_exc
 from neutron_lib.plugins import directory
 from oslo_config import cfg
@@ -126,7 +127,7 @@ class QuotaSetsController(wsgi.Controller):
         return {self._resource_name: self._get_quotas(request, id)}
 
 
-class Quotasv2(extensions.ExtensionDescriptor):
+class Quotasv2(api_extensions.ExtensionDescriptor):
     """Quotas management support."""
 
     @classmethod
diff --git a/neutron/extensions/rbac.py b/neutron/extensions/rbac.py
index 03ed5c53f87..a16d4162ee4 100644
--- a/neutron/extensions/rbac.py
+++ b/neutron/extensions/rbac.py
@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib import exceptions as n_exc
 from neutron_lib.plugins import directory
 
@@ -81,7 +82,7 @@ RESOURCE_ATTRIBUTE_MAP = {
 quota.register_quota_opts(quota.rbac_quota_opts)
 
 
-class Rbac(extensions.ExtensionDescriptor):
+class Rbac(api_extensions.ExtensionDescriptor):
     """RBAC policy support."""
 
     @classmethod
diff --git a/neutron/extensions/revisions.py b/neutron/extensions/revisions.py
index b36a9ff2ee3..1aafb7b4467 100644
--- a/neutron/extensions/revisions.py
+++ b/neutron/extensions/revisions.py
@@ -11,7 +11,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from neutron.api import extensions
+from neutron_lib.api import extensions
+
 from neutron.db import standard_attr
 
 
diff --git a/neutron/extensions/router_availability_zone.py b/neutron/extensions/router_availability_zone.py
index 3e09bb302c3..053eb791b5f 100644
--- a/neutron/extensions/router_availability_zone.py
+++ b/neutron/extensions/router_availability_zone.py
@@ -14,9 +14,9 @@
 
 import abc
 
+from neutron_lib.api import extensions
 import six
 
-from neutron.api import extensions
 from neutron.extensions import availability_zone as az_ext
 
 
diff --git a/neutron/extensions/routerservicetype.py b/neutron/extensions/routerservicetype.py
index e40ffa59fd2..5e4ffbfb3a8 100644
--- a/neutron/extensions/routerservicetype.py
+++ b/neutron/extensions/routerservicetype.py
@@ -12,7 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from neutron.api import extensions
+from neutron_lib.api import extensions
 
 SERVICE_TYPE_ID = 'service_type_id'
 EXTENDED_ATTRIBUTES_2_0 = {
diff --git a/neutron/extensions/securitygroup.py b/neutron/extensions/securitygroup.py
index c02ff76b537..cd0319e055f 100644
--- a/neutron/extensions/securitygroup.py
+++ b/neutron/extensions/securitygroup.py
@@ -16,6 +16,7 @@
 import abc
 
 import netaddr
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib.api import validators
 from neutron_lib import constants as const
 from neutron_lib import exceptions as nexception
@@ -281,7 +282,7 @@ EXTENDED_ATTRIBUTES_2_0 = {
 quota.register_quota_opts(quota.security_group_quota_opts)
 
 
-class Securitygroup(extensions.ExtensionDescriptor):
+class Securitygroup(api_extensions.ExtensionDescriptor):
     """Security group extension."""
 
     @classmethod
diff --git a/neutron/extensions/segment.py b/neutron/extensions/segment.py
index a178c9f5562..134a30eb31b 100644
--- a/neutron/extensions/segment.py
+++ b/neutron/extensions/segment.py
@@ -16,6 +16,7 @@ import abc
 import six
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib import constants
 from neutron_lib.plugins import directory
 
@@ -88,7 +89,7 @@ RESOURCE_ATTRIBUTE_MAP = {
 }
 
 
-class Segment(extensions.ExtensionDescriptor):
+class Segment(api_extensions.ExtensionDescriptor):
     """Extension class supporting Segments."""
 
     @classmethod
diff --git a/neutron/extensions/servicetype.py b/neutron/extensions/servicetype.py
index ef18f09cd5b..567d22360dc 100644
--- a/neutron/extensions/servicetype.py
+++ b/neutron/extensions/servicetype.py
@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from neutron_lib.api import extensions as api_extensions
+
 from neutron._i18n import _
 from neutron.api import extensions
 from neutron.api.v2 import base
@@ -40,7 +42,7 @@ RESOURCE_ATTRIBUTE_MAP = {
 }
 
 
-class Servicetype(extensions.ExtensionDescriptor):
+class Servicetype(api_extensions.ExtensionDescriptor):
 
     @classmethod
     def get_name(cls):
diff --git a/neutron/extensions/sorting.py b/neutron/extensions/sorting.py
index 48f9a5d33a0..f03b3c10caf 100644
--- a/neutron/extensions/sorting.py
+++ b/neutron/extensions/sorting.py
@@ -11,13 +11,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from neutron_lib.api import extensions as api_extensions
+
 from neutron.api import extensions
 
 
 _ALIAS = 'sorting'
 
 
-class Sorting(extensions.ExtensionDescriptor):
+class Sorting(api_extensions.ExtensionDescriptor):
     """Fake extension that indicates that sorting is enabled."""
 
     extensions.register_custom_supported_check(
diff --git a/neutron/extensions/standardattrdescription.py b/neutron/extensions/standardattrdescription.py
index 983f8a4ced6..dbd2a778b6d 100644
--- a/neutron/extensions/standardattrdescription.py
+++ b/neutron/extensions/standardattrdescription.py
@@ -13,7 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from neutron.api import extensions
+from neutron_lib.api import extensions
+
 from neutron.api.v2 import attributes as attr
 from neutron.db import standard_attr
 
diff --git a/neutron/extensions/subnet_service_types.py b/neutron/extensions/subnet_service_types.py
index 773aa2381b1..23611463d42 100644
--- a/neutron/extensions/subnet_service_types.py
+++ b/neutron/extensions/subnet_service_types.py
@@ -10,13 +10,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from neutron_lib.api import extensions
 from neutron_lib.api import validators
 from neutron_lib import constants
 from neutron_lib import exceptions
 import webob.exc
 
 from neutron._i18n import _
-from neutron.api import extensions
 from neutron.api.v2 import attributes
 
 
diff --git a/neutron/extensions/subnetallocation.py b/neutron/extensions/subnetallocation.py
index 73393182b0f..3f5b82b8b72 100644
--- a/neutron/extensions/subnetallocation.py
+++ b/neutron/extensions/subnetallocation.py
@@ -13,10 +13,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from neutron_lib.api import extensions
 from neutron_lib import constants
 
-from neutron.api import extensions
-
 
 class Subnetallocation(extensions.ExtensionDescriptor):
     """Extension class supporting subnet allocation."""
diff --git a/neutron/extensions/tag.py b/neutron/extensions/tag.py
index 1ca12059aec..9b195b43c5d 100644
--- a/neutron/extensions/tag.py
+++ b/neutron/extensions/tag.py
@@ -13,6 +13,7 @@
 
 import abc
 
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib.api import validators
 from neutron_lib import exceptions
 from neutron_lib.plugins import directory
@@ -121,7 +122,7 @@ class TagController(object):
         return self.plugin.delete_tags(request.context, parent, parent_id)
 
 
-class Tag(extensions.ExtensionDescriptor):
+class Tag(api_extensions.ExtensionDescriptor):
     """Extension class supporting tags."""
 
     @classmethod
diff --git a/neutron/extensions/timestamp.py b/neutron/extensions/timestamp.py
index 26ae0917ca6..41e50409f72 100644
--- a/neutron/extensions/timestamp.py
+++ b/neutron/extensions/timestamp.py
@@ -12,7 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from neutron.api import extensions
+from neutron_lib.api import extensions
+
 from neutron.db import standard_attr
 
 
diff --git a/neutron/extensions/trunk.py b/neutron/extensions/trunk.py
index bc5a162b73c..07737435b2e 100644
--- a/neutron/extensions/trunk.py
+++ b/neutron/extensions/trunk.py
@@ -14,8 +14,8 @@
 #    under the License.
 
 from neutron_lib.api.definitions import trunk
+from neutron_lib.api import extensions
 
-from neutron.api import extensions
 from neutron.api.v2 import resource_helper
 
 
diff --git a/neutron/extensions/trunk_details.py b/neutron/extensions/trunk_details.py
index 9a9459ae7e9..4bb5a68f763 100644
--- a/neutron/extensions/trunk_details.py
+++ b/neutron/extensions/trunk_details.py
@@ -13,8 +13,7 @@
 #    under the License.
 
 from neutron_lib.api.definitions import trunk_details
-
-from neutron.api import extensions
+from neutron_lib.api import extensions
 
 
 # NOTE(armax): because of the API machinery, this extension must be on
diff --git a/neutron/extensions/vlantransparent.py b/neutron/extensions/vlantransparent.py
index 91b057ed4f0..36938935fa5 100644
--- a/neutron/extensions/vlantransparent.py
+++ b/neutron/extensions/vlantransparent.py
@@ -13,6 +13,7 @@
 #    under the License.
 
 from neutron_lib.api import converters
+from neutron_lib.api import extensions
 from neutron_lib.api import validators
 from neutron_lib import constants
 from neutron_lib import exceptions
@@ -20,7 +21,6 @@ from oslo_config import cfg
 from oslo_log import log as logging
 
 from neutron._i18n import _, _LI
-from neutron.api import extensions
 
 LOG = logging.getLogger(__name__)
 
diff --git a/neutron/tests/functional/pecan_wsgi/utils.py b/neutron/tests/functional/pecan_wsgi/utils.py
index 1188c5ee6a6..39b529878bc 100644
--- a/neutron/tests/functional/pecan_wsgi/utils.py
+++ b/neutron/tests/functional/pecan_wsgi/utils.py
@@ -10,13 +10,15 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from neutron_lib.api import extensions as api_extensions
+
 from neutron.api import extensions
 from neutron.api.v2 import base
 from neutron.pecan_wsgi import controllers
 from neutron.pecan_wsgi.controllers import utils as pecan_utils
 
 
-class FakeSingularCollectionExtension(extensions.ExtensionDescriptor):
+class FakeSingularCollectionExtension(api_extensions.ExtensionDescriptor):
 
     COLLECTION = 'topologies'
     RESOURCE = 'topology'
@@ -104,7 +106,7 @@ def create_router(context, l3_plugin):
           'admin_state_up': True}})
 
 
-class FakeExtension(extensions.ExtensionDescriptor):
+class FakeExtension(api_extensions.ExtensionDescriptor):
 
     HYPHENATED_RESOURCE = 'meh_meh'
     HYPHENATED_COLLECTION = HYPHENATED_RESOURCE + 's'
diff --git a/neutron/tests/unit/extension_stubs.py b/neutron/tests/unit/extension_stubs.py
index 99b2ec1de5d..ab0e19c4363 100644
--- a/neutron/tests/unit/extension_stubs.py
+++ b/neutron/tests/unit/extension_stubs.py
@@ -15,11 +15,13 @@
 
 import abc
 
+from neutron_lib.api import extensions as api_extensions
+
 from neutron.api import extensions
 from neutron import wsgi
 
 
-class StubExtension(extensions.ExtensionDescriptor):
+class StubExtension(api_extensions.ExtensionDescriptor):
 
     def __init__(self, alias="stub_extension", optional=None):
         self.alias = alias
diff --git a/neutron/tests/unit/extensions/extendedattribute.py b/neutron/tests/unit/extensions/extendedattribute.py
index 2f2f2de1594..d35f453caf9 100644
--- a/neutron/tests/unit/extensions/extendedattribute.py
+++ b/neutron/tests/unit/extensions/extendedattribute.py
@@ -12,7 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from neutron.api import extensions
+from neutron_lib.api import extensions
 
 EXTENDED_ATTRIBUTE = 'extended_attribute'
 EXTENDED_ATTRIBUTES_2_0 = {
diff --git a/neutron/tests/unit/extensions/extensionattribute.py b/neutron/tests/unit/extensions/extensionattribute.py
index a17857fd003..f529e935ef7 100644
--- a/neutron/tests/unit/extensions/extensionattribute.py
+++ b/neutron/tests/unit/extensions/extensionattribute.py
@@ -15,6 +15,7 @@
 
 import abc
 
+from neutron_lib.api import extensions as api_extensions
 from neutron_lib.plugins import directory
 
 from neutron.api import extensions
@@ -39,7 +40,7 @@ RESOURCE_ATTRIBUTE_MAP = {
 }
 
 
-class Extensionattribute(extensions.ExtensionDescriptor):
+class Extensionattribute(api_extensions.ExtensionDescriptor):
 
     @classmethod
     def get_name(cls):
diff --git a/neutron/tests/unit/extensions/foxinsocks.py b/neutron/tests/unit/extensions/foxinsocks.py
index 1edde476790..e63d6ff15b2 100644
--- a/neutron/tests/unit/extensions/foxinsocks.py
+++ b/neutron/tests/unit/extensions/foxinsocks.py
@@ -15,6 +15,7 @@
 
 import abc
 
+from neutron_lib.api import extensions as api_extensions
 from oslo_serialization import jsonutils
 import six
 
@@ -36,7 +37,7 @@ class FoxInSocksPluginInterface(extensions.PluginInterface):
         pass
 
 
-class Foxinsocks(extensions.ExtensionDescriptor):
+class Foxinsocks(api_extensions.ExtensionDescriptor):
 
     def __init__(self):
         pass
diff --git a/neutron/tests/unit/extensions/v2attributes.py b/neutron/tests/unit/extensions/v2attributes.py
index 2adfcc12fa6..0c83e2c1b36 100644
--- a/neutron/tests/unit/extensions/v2attributes.py
+++ b/neutron/tests/unit/extensions/v2attributes.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from neutron.api import extensions
+from neutron_lib.api import extensions
 
 
 EXTENDED_ATTRIBUTES_2_0 = {
diff --git a/neutron/tests/unit/plugins/ml2/extensions/fake_extension.py b/neutron/tests/unit/plugins/ml2/extensions/fake_extension.py
index d247c7d392c..7196996dd34 100644
--- a/neutron/tests/unit/plugins/ml2/extensions/fake_extension.py
+++ b/neutron/tests/unit/plugins/ml2/extensions/fake_extension.py
@@ -10,10 +10,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from neutron_lib.api import extensions
 from neutron_lib import constants
 
 from neutron._i18n import _
-from neutron.api import extensions
 
 
 EXTENDED_ATTRIBUTES_2_0 = {