diff --git a/config.yaml b/config.yaml
index 3d92376b..6bf27e47 100644
--- a/config.yaml
+++ b/config.yaml
@@ -173,15 +173,3 @@ options:
     description: |
       Default multicast port number that will be used to communicate between
       HA Cluster nodes.
-  phy-nics:
-    type: string
-    default:
-    description: |
-      A space-separated list of NICs that we want phy-nic-mtu applied to.
-  phy-nic-mtu:
-    type: int
-    default:
-    description: |
-      To improve network performance of VM, sometimes we should keep VM MTU as
-      1500 and use charm to modify MTU of tunnel nic more than 1500 (e.g. 1546
-      for GRE).
diff --git a/hooks/quantum_contexts.py b/hooks/quantum_contexts.py
index be6e7fee..03459142 100644
--- a/hooks/quantum_contexts.py
+++ b/hooks/quantum_contexts.py
@@ -191,27 +191,14 @@ class ExternalPortContext(NeutronPortContext):
             ports = self.resolve_ports(ports)
             if ports:
                 ctxt = {"ext_port": ports[0]}
-                mtu = config('phy-nic-mtu')
+                neutron_api_settings = _neutron_api_settings()
+                mtu = neutron_api_settings.get('network_device_mtu')
                 if mtu:
                     ctxt['ext_port_mtu'] = mtu
 
         return ctxt
 
 
-class PhyNICMTUContext(OSContextGenerator):
-
-    def __call__(self):
-        ctxt = {}
-        port = config('phy-nics')
-        if port:
-            ctxt = {"devs": port.replace(' ', '\\n')}
-            mtu = config('phy-nic-mtu')
-            if mtu:
-                ctxt['mtu'] = mtu
-
-        return ctxt
-
-
 class DataPortContext(NeutronPortContext):
 
     def __call__(self):
@@ -231,6 +218,22 @@ class DataPortContext(NeutronPortContext):
         return None
 
 
+class PhyNICMTUContext(DataPortContext):
+
+    def __call__(self):
+        ctxt = {}
+        mappings = super(PhyNICMTUContext, self).__call__()
+        if mappings and mappings.values():
+            ports = mappings.values()
+            neutron_api_settings = _neutron_api_settings()
+            mtu = neutron_api_settings.get('network_device_mtu')
+            if mtu:
+                ctxt["devs"] = '\\n'.join(ports)
+                ctxt['mtu'] = mtu
+
+        return ctxt
+
+
 class QuantumGatewayContext(OSContextGenerator):
 
     def __call__(self):
diff --git a/unit_tests/test_quantum_contexts.py b/unit_tests/test_quantum_contexts.py
index 03ef3247..d983cde3 100644
--- a/unit_tests/test_quantum_contexts.py
+++ b/unit_tests/test_quantum_contexts.py
@@ -181,6 +181,7 @@ class TestNeutronPortContext(CharmTestCase):
 
         self.assertEquals(quantum_contexts.ExternalPortContext()(), {})
 
+    @patch.object(quantum_contexts, '_neutron_api_settings')
     @patch('charmhelpers.contrib.openstack.context.get_nic_hwaddr')
     @patch('charmhelpers.contrib.openstack.context.list_nics')
     @patch('charmhelpers.contrib.openstack.context.get_ipv6_addr')
@@ -189,8 +190,10 @@ class TestNeutronPortContext(CharmTestCase):
     def test_ext_port_mac_one_used_nic(self, mock_config,
                                        mock_get_ipv4_addr,
                                        mock_get_ipv6_addr, mock_list_nics,
-                                       mock_get_nic_hwaddr):
+                                       mock_get_nic_hwaddr,
+                                       mock_neutron_api_settings):
 
+        mock_neutron_api_settings.return_value = {'network_device_mtu': 1234}
         config_macs = "%s %s" % (self.machine_macs['eth1'],
                                  self.machine_macs['eth2'])
 
@@ -199,8 +202,7 @@ class TestNeutronPortContext(CharmTestCase):
         mock_list_nics.return_value = self.machine_macs.keys()
         mock_get_nic_hwaddr.side_effect = self._fake_get_hwaddr
 
-        config = self.fake_config({'ext-port': config_macs,
-                                   'phy-nic-mtu': 1234})
+        config = self.fake_config({'ext-port': config_macs})
         self.config.side_effect = config
         mock_config.side_effect = config
         self.assertEquals(quantum_contexts.ExternalPortContext()(),