diff --git a/quantum/plugins/cisco/common/cisco_exceptions.py b/quantum/plugins/cisco/common/cisco_exceptions.py
index 149da5d361..2623f745cf 100644
--- a/quantum/plugins/cisco/common/cisco_exceptions.py
+++ b/quantum/plugins/cisco/common/cisco_exceptions.py
@@ -183,3 +183,9 @@ class InvalidAttach(exceptions.QuantumException):
                 "attachment ID with port ID happens implicitly when "
                 "VM is instantiated; attach operation can be "
                 "performed subsequently.")
+
+
+class InvalidDetach(exceptions.QuantumException):
+    message = _("Unable to unplug the attachment %(att_id)s from port "
+                "%(port_id)s for network %(net_id)s. The attachment "
+                "%(att_id)s does not exist.")
diff --git a/quantum/plugins/cisco/l2network_plugin.py b/quantum/plugins/cisco/l2network_plugin.py
index ae03ac4396..6c6787b987 100644
--- a/quantum/plugins/cisco/l2network_plugin.py
+++ b/quantum/plugins/cisco/l2network_plugin.py
@@ -288,8 +288,8 @@ class L2Network(QuantumPluginBase):
         port = db.port_get(net_id, port_id)
         attachment_id = port[const.INTERFACEID]
         if attachment_id is None:
-            raise exc.InvalidDetach(port_id=port_id, net_id=net_id,
-                                    att_id=remote_interface_id)
+            raise cexc.InvalidDetach(port_id=port_id, net_id=net_id,
+                                     att_id=remote_interface_id)
         self._invoke_device_plugins(self._func_name(), [tenant_id, net_id,
                                                         port_id])
         attachment_id = attachment_id[:const.UUID_LENGTH]