diff --git a/neutron_lib/api/definitions/metering.py b/neutron_lib/api/definitions/metering.py
index ab1caac70..336303a4c 100644
--- a/neutron_lib/api/definitions/metering.py
+++ b/neutron_lib/api/definitions/metering.py
@@ -15,6 +15,7 @@
 from neutron_lib.api import converters
 from neutron_lib import constants
 from neutron_lib.db import constants as db_const
+from neutron_lib.services.qos import constants as qos_consts
 
 
 METERING_LABELS = 'metering_labels'
@@ -76,11 +77,11 @@ RESOURCE_ATTRIBUTE_MAP = {
             'is_filter': True, 'is_sort_key': True,
             'is_visible': True, 'required_by_policy': True
         },
-        'direction': {
+        qos_consts.DIRECTION: {
             'allow_post': True, 'allow_put': False,
             'is_visible': True, 'is_filter': True,
             'is_sort_key': True,
-            'validate': {'type:values': ['ingress', 'egress']}
+            'validate': {'type:values': constants.VALID_DIRECTIONS}
         },
         'excluded': {
             'allow_post': True, 'allow_put': False,
diff --git a/neutron_lib/api/definitions/qos.py b/neutron_lib/api/definitions/qos.py
index d8862042a..2b76990ba 100644
--- a/neutron_lib/api/definitions/qos.py
+++ b/neutron_lib/api/definitions/qos.py
@@ -116,7 +116,7 @@ SUB_RESOURCE_ATTRIBUTE_MAP = {
         'parent': _PARENT,
         'parameters': dict(
             _QOS_RULE_COMMON_FIELDS,
-            **{'max_kbps': {
+            **{qos_const.MAX_KBPS: {
                 'allow_post': True, 'allow_put': True,
                 'convert_to': converters.convert_to_int,
                 'is_visible': True,
@@ -125,7 +125,7 @@ SUB_RESOURCE_ATTRIBUTE_MAP = {
                 'validate': {
                     'type:range': [0, db_const.DB_INTEGER_MAX_VALUE]}
             },
-                'max_burst_kbps': {
+                qos_const.MAX_BURST: {
                     'allow_post': True, 'allow_put': True,
                     'is_visible': True, 'default': 0,
                     'is_filter': True,
@@ -138,7 +138,7 @@ SUB_RESOURCE_ATTRIBUTE_MAP = {
         'parent': _PARENT,
         'parameters': dict(
             _QOS_RULE_COMMON_FIELDS,
-            **{'dscp_mark': {
+            **{qos_const.DSCP_MARK: {
                 'allow_post': True, 'allow_put': True,
                 'convert_to': converters.convert_to_int,
                 'is_visible': True,
@@ -151,7 +151,7 @@ SUB_RESOURCE_ATTRIBUTE_MAP = {
         'parent': _PARENT,
         'parameters': dict(
             _QOS_RULE_COMMON_FIELDS,
-            **{'min_kbps': {
+            **{qos_const.MIN_KBPS: {
                 'allow_post': True, 'allow_put': True,
                 'is_visible': True,
                 'is_filter': True,
@@ -159,7 +159,7 @@ SUB_RESOURCE_ATTRIBUTE_MAP = {
                 'convert_to': converters.convert_to_int,
                 'validate': {
                     'type:range': [0, db_const.DB_INTEGER_MAX_VALUE]}},
-                'direction': {
+                qos_const.DIRECTION: {
                     'allow_post': True, 'allow_put': True,
                     'is_visible': True, 'default': constants.EGRESS_DIRECTION,
                     'is_filter': True,
diff --git a/neutron_lib/api/definitions/qos_bw_limit_direction.py b/neutron_lib/api/definitions/qos_bw_limit_direction.py
index ab99b6cc7..0b9bb393e 100644
--- a/neutron_lib/api/definitions/qos_bw_limit_direction.py
+++ b/neutron_lib/api/definitions/qos_bw_limit_direction.py
@@ -15,10 +15,9 @@
 
 from neutron_lib.api.definitions import qos as qos_apidef
 from neutron_lib import constants
+from neutron_lib.services.qos import constants as qos_const
 
 
-DIRECTION = 'direction'
-
 ALIAS = 'qos-bw-limit-direction'
 LABEL = ''
 IS_SHIM_EXTENSION = False
@@ -34,7 +33,7 @@ SUB_RESOURCE_ATTRIBUTE_MAP = {
     # sub-resource extension itself
     qos_apidef.BANDWIDTH_LIMIT_RULES: {
         'parameters': {
-            DIRECTION: {
+            qos_const.DIRECTION: {
                 'allow_post': True,
                 'allow_put': True,
                 'is_visible': True,
diff --git a/neutron_lib/api/definitions/qos_rules_alias.py b/neutron_lib/api/definitions/qos_rules_alias.py
index 2a868a6c4..5e23413c1 100644
--- a/neutron_lib/api/definitions/qos_rules_alias.py
+++ b/neutron_lib/api/definitions/qos_rules_alias.py
@@ -55,7 +55,7 @@ RESOURCE_ATTRIBUTE_MAP = {
                     'type:range': [0, db_const.DB_INTEGER_MAX_VALUE]
                 }
             },
-            qos_bw_limit_direction.DIRECTION: {
+            q_const.DIRECTION: {
                 'allow_post': False,
                 'allow_put': True,
                 'is_visible': True,
@@ -100,7 +100,7 @@ RESOURCE_ATTRIBUTE_MAP = {
                     'type:range': [0, db_const.DB_INTEGER_MAX_VALUE]
                 }
             },
-            qos_bw_limit_direction.DIRECTION: {
+            q_const.DIRECTION: {
                 'allow_post': False, 'allow_put': True,
                 'is_visible': True, 'default': constants.EGRESS_DIRECTION,
                 'is_filter': True,
diff --git a/neutron_lib/tests/unit/api/definitions/test_metering.py b/neutron_lib/tests/unit/api/definitions/test_metering.py
index 93f488d5e..c959c54ae 100644
--- a/neutron_lib/tests/unit/api/definitions/test_metering.py
+++ b/neutron_lib/tests/unit/api/definitions/test_metering.py
@@ -11,6 +11,7 @@
 #    under the License.
 
 from neutron_lib.api.definitions import metering
+from neutron_lib.services.qos import constants as qos_consts
 from neutron_lib.tests.unit.api.definitions import base
 
 
@@ -21,4 +22,4 @@ class MeteringDefinitionTestCase(base.DefinitionBaseTestCase):
     extension_attributes = ('remote_ip_prefix',
                             'excluded',
                             'metering_label_id',
-                            'direction')
+                            qos_consts.DIRECTION)
diff --git a/neutron_lib/tests/unit/api/definitions/test_qos.py b/neutron_lib/tests/unit/api/definitions/test_qos.py
index 6009672ce..eec5675bb 100644
--- a/neutron_lib/tests/unit/api/definitions/test_qos.py
+++ b/neutron_lib/tests/unit/api/definitions/test_qos.py
@@ -11,6 +11,7 @@
 #    under the License.
 
 from neutron_lib.api.definitions import qos
+from neutron_lib.services.qos import constants as q_const
 from neutron_lib.tests.unit.api.definitions import base
 
 
@@ -20,6 +21,6 @@ class QoSDefinitionTestCase(base.DefinitionBaseTestCase):
     extension_subresources = (qos.BANDWIDTH_LIMIT_RULES,
                               qos.DSCP_MARKING_RULES,
                               qos.MIN_BANDWIDTH_RULES)
-    extension_attributes = ('direction', 'max_burst_kbps', 'type',
-                            'dscp_mark', 'min_kbps', 'rules', 'max_kbps',
-                            'qos_policy_id')
+    extension_attributes = (q_const.DIRECTION, q_const.MAX_BURST, 'type',
+                            q_const.DSCP_MARK, q_const.MIN_KBPS, 'rules',
+                            q_const.MAX_KBPS, q_const.QOS_POLICY_ID)
diff --git a/neutron_lib/tests/unit/api/definitions/test_qos_bw_limit_direction.py b/neutron_lib/tests/unit/api/definitions/test_qos_bw_limit_direction.py
index 15a6a4bdd..4caa6f29b 100644
--- a/neutron_lib/tests/unit/api/definitions/test_qos_bw_limit_direction.py
+++ b/neutron_lib/tests/unit/api/definitions/test_qos_bw_limit_direction.py
@@ -15,10 +15,11 @@
 
 from neutron_lib.api.definitions import qos
 from neutron_lib.api.definitions import qos_bw_limit_direction
+from neutron_lib.services.qos import constants as qos_const
 from neutron_lib.tests.unit.api.definitions import base
 
 
 class QoSBwLimitDirectionDefinitionTestCase(base.DefinitionBaseTestCase):
     extension_module = qos_bw_limit_direction
     extension_subresources = (qos.BANDWIDTH_LIMIT_RULES,)
-    extension_attributes = (qos_bw_limit_direction.DIRECTION,)
+    extension_attributes = (qos_const.DIRECTION,)
diff --git a/neutron_lib/tests/unit/api/definitions/test_qos_rules_alias.py b/neutron_lib/tests/unit/api/definitions/test_qos_rules_alias.py
index f7fcb3145..9fac32b34 100644
--- a/neutron_lib/tests/unit/api/definitions/test_qos_rules_alias.py
+++ b/neutron_lib/tests/unit/api/definitions/test_qos_rules_alias.py
@@ -11,7 +11,6 @@
 #    under the License.
 
 from neutron_lib.api.definitions import qos
-from neutron_lib.api.definitions import qos_bw_limit_direction
 from neutron_lib.api.definitions import qos_rules_alias
 from neutron_lib.services.qos import constants as q_const
 from neutron_lib.tests.unit.api.definitions import base
@@ -22,7 +21,7 @@ class QoSRulesAliasDefinitionTestCase(base.DefinitionBaseTestCase):
     extension_resources = (qos.BANDWIDTH_LIMIT_RULES,
                            qos.DSCP_MARKING_RULES,
                            qos.MIN_BANDWIDTH_RULES)
-    extension_attributes = (qos_bw_limit_direction.DIRECTION,
+    extension_attributes = (q_const.DIRECTION,
                             q_const.MAX_BURST,
                             q_const.DSCP_MARK,
                             q_const.MIN_KBPS,
diff --git a/neutron_lib/tests/unit/services/qos/test_base.py b/neutron_lib/tests/unit/services/qos/test_base.py
index 82e9e5cb9..d4aee1e0b 100644
--- a/neutron_lib/tests/unit/services/qos/test_base.py
+++ b/neutron_lib/tests/unit/services/qos/test_base.py
@@ -15,6 +15,7 @@
 import mock
 
 from neutron_lib.api.definitions import portbindings
+from neutron_lib import constants
 from neutron_lib.services.qos import base as qos_base
 from neutron_lib.services.qos import constants as qos_consts
 from neutron_lib.tests import _base
@@ -22,8 +23,8 @@ from neutron_lib.tests import _base
 
 SUPPORTED_RULES = {
     qos_consts.RULE_TYPE_MINIMUM_BANDWIDTH: {
-        "min_kbps": {'type:values': None},
-        'direction': {'type:values': ['egress']}
+        qos_consts.MIN_KBPS: {'type:values': None},
+        qos_consts.DIRECTION: {'type:values': ['egress']}
     }
 }
 
@@ -73,9 +74,13 @@ class TestDriverBase(_base.BaseTestCase):
             _make_driver().is_rule_supported(
                 _make_rule(
                     rule_type=qos_consts.RULE_TYPE_MINIMUM_BANDWIDTH,
-                    params={'min_kbps': None, 'direction': 'egress'})))
+                    params={qos_consts.MIN_KBPS: None,
+                            qos_consts.DIRECTION:
+                                constants.EGRESS_DIRECTION})))
         self.assertFalse(
             _make_driver().is_rule_supported(
                 _make_rule(
                     rule_type=qos_consts.RULE_TYPE_MINIMUM_BANDWIDTH,
-                    params={'min_kbps': None, 'direction': 'ingress'})))
+                    params={qos_consts.MIN_KBPS: None,
+                            qos_consts.DIRECTION:
+                                constants.INGRESS_DIRECTION})))