diff --git a/neutron_taas/services/taas/drivers/linux/ovs_taas.py b/neutron_taas/services/taas/drivers/linux/ovs_taas.py
index 6ffb5858..52b8cdd2 100644
--- a/neutron_taas/services/taas/drivers/linux/ovs_taas.py
+++ b/neutron_taas/services/taas/drivers/linux/ovs_taas.py
@@ -17,7 +17,7 @@
 from neutron.agent.common import ovs_lib
 from neutron.agent.linux import utils
 from neutron.conf.agent import common
-from neutron_lib import constants as n_consts
+from neutron_lib.plugins.ml2 import ovs_constants as n_ovs_consts
 
 from neutron_taas.services.taas.agents.extensions import taas as taas_base
 import neutron_taas.services.taas.drivers.linux.ovs_constants \
@@ -236,8 +236,8 @@ class OvsTaasDriver(taas_base.TaasAgentDriver):
                              actions="output:%s" % str(patch_tap_int_id))
 
         # Add flow(s) in br-tun
-        for tunnel_type in n_consts.TUNNEL_NETWORK_TYPES:
-            self.tun_br.add_flow(table=n_consts.TUN_TABLE[tunnel_type],
+        for tunnel_type in n_ovs_consts.TUNNEL_NETWORK_TYPES:
+            self.tun_br.add_flow(table=n_ovs_consts.TUN_TABLE[tunnel_type],
                                  priority=1,
                                  tun_id=taas_id,
                                  actions=(
@@ -294,8 +294,8 @@ class OvsTaasDriver(taas_base.TaasAgentDriver):
                                  dl_vlan=taas_id)
 
         # Delete flow(s) from br-tun
-        for tunnel_type in n_consts.TUNNEL_NETWORK_TYPES:
-            self.tun_br.delete_flows(table=n_consts.TUN_TABLE[tunnel_type],
+        for tunnel_type in n_ovs_consts.TUNNEL_NETWORK_TYPES:
+            self.tun_br.delete_flows(table=n_ovs_consts.TUN_TABLE[tunnel_type],
                                      tun_id=taas_id)
 
         self.tun_br.delete_flows(table=taas_ovs_consts.TAAS_DST_CHECK,
@@ -363,8 +363,8 @@ class OvsTaasDriver(taas_base.TaasAgentDriver):
             #                                    patch_int_tap_id)
 
         # Add flow(s) in br-tun
-        for tunnel_type in n_consts.TUNNEL_NETWORK_TYPES:
-            self.tun_br.add_flow(table=n_consts.TUN_TABLE[tunnel_type],
+        for tunnel_type in n_ovs_consts.TUNNEL_NETWORK_TYPES:
+            self.tun_br.add_flow(table=n_ovs_consts.TUN_TABLE[tunnel_type],
                                  priority=1,
                                  tun_id=taas_id,
                                  actions=(