diff --git a/neutron/plugins/ml2/driver_context.py b/neutron/plugins/ml2/driver_context.py
index f0503138e68..d18bb25d6c2 100644
--- a/neutron/plugins/ml2/driver_context.py
+++ b/neutron/plugins/ml2/driver_context.py
@@ -38,12 +38,15 @@ class MechanismDriverContext(object):
 class NetworkContext(MechanismDriverContext, api.NetworkContext):
 
     def __init__(self, plugin, plugin_context, network,
-                 original_network=None):
+                 original_network=None, segments=None):
         super(NetworkContext, self).__init__(plugin, plugin_context)
         self._network = network
         self._original_network = original_network
-        self._segments = segments_db.get_network_segments(
-            plugin_context.session, network['id'])
+        if segments is None:
+            self._segments = segments_db.get_network_segments(
+                plugin_context.session, network['id'])
+        else:
+            self._segments = segments
 
     @property
     def current(self):
@@ -88,8 +91,11 @@ class PortContext(MechanismDriverContext, api.PortContext):
         super(PortContext, self).__init__(plugin, plugin_context)
         self._port = port
         self._original_port = original_port
-        self._network_context = NetworkContext(plugin, plugin_context,
-                                               network) if network else None
+        if isinstance(network, NetworkContext):
+            self._network_context = network
+        else:
+            self._network_context = NetworkContext(
+                plugin, plugin_context, network) if network else None
         self._binding = binding
         self._binding_levels = binding_levels
         self._segments_to_bind = None