diff --git a/openflow_input/bsn_vport b/openflow_input/bsn_vport
index 8e02794..af0b579 100644
--- a/openflow_input/bsn_vport
+++ b/openflow_input/bsn_vport
@@ -30,6 +30,13 @@
 
 #version any
 
+// When the ingress or egress VID has this value, no outer tag should be used.
+// In this case, the corresponding TPID is ignored.
+
+enum ofp_bsn_vport_q_in_q_untagged {
+    OF_BSN_VPORT_Q_IN_Q_UNTAGGED = 0xffff,
+};
+
 // BSN Virtual port object header
 // FIXME For now, inheritance is not exercised.  See below.
 struct ofp_bsn_vport {
@@ -39,10 +46,6 @@
 };
 
 
-// When the ingress or egress VID has this value, no outer tag should be used.
-// In this case, the corresponding TPID is ignored.
-// #define OF_BSN_VPORT_Q_IN_Q_UNTAGGED 0xffff
-
 // Q-in-Q virtual port specification
 
 struct of_bsn_vport_q_in_q {