diff --git a/loxi_front_end/parser.py b/loxi_front_end/parser.py
index 4a465f7..fbf476d 100644
--- a/loxi_front_end/parser.py
+++ b/loxi_front_end/parser.py
@@ -68,7 +68,7 @@
          s('}') - s(';')
 
 # Enums
-enum_param_name = kw("wire_type") | kw("bitmask") | kw("complete")
+enum_param_name = kw("wire_type") | kw("bitmask") | kw("complete") | kw("stable")
 enum_param = P.Group(enum_param_name  - s('=') - word)
 enum_param_list = P.Forward()
 enum_param_list << enum_param + P.Optional(s(',') + P.Optional(enum_param_list))
diff --git a/loxi_ir/unified.py b/loxi_ir/unified.py
index 41b86dc..fa97c87 100644
--- a/loxi_ir/unified.py
+++ b/loxi_ir/unified.py
@@ -98,6 +98,9 @@
                     self.entries[e.name] = ir.OFEnumEntry(e.name, e.value, copy.copy(e.params))
                 else:
                     entry = self.entries[e.name]
+                    if v_enum.params.get('stable') == 'True' and e.value != entry.value:
+                        raise Exception("Error unifying stable ir enum {} - adding entry {} version {} value {} <-> {}".format(
+                            self.name, e.name, version, entry.value, e.value))
                     for name, value in e.params.items():
                         if not name in entry.params:
                             entry.params[name] = value
diff --git a/openflow_input/bsn_port_counter b/openflow_input/bsn_port_counter
index 73ba80e..83cd1c8 100644
--- a/openflow_input/bsn_port_counter
+++ b/openflow_input/bsn_port_counter
@@ -30,7 +30,7 @@
 
 #version 4
 
-enum ofp_bsn_port_counter(wire_type=uint8_t, complete=False) {
+enum ofp_bsn_port_counter(wire_type=uint8_t, complete=False, stable=True) {
   OFP_BSN_PORT_COUNTER_RX_BYTES = 0,
   OFP_BSN_PORT_COUNTER_RX_PACKETS_UNICAST = 1,
   OFP_BSN_PORT_COUNTER_RX_PACKETS_BROADCAST = 2,
diff --git a/openflow_input/bsn_vlan_counter b/openflow_input/bsn_vlan_counter
index c88d6b7..c5814f4 100644
--- a/openflow_input/bsn_vlan_counter
+++ b/openflow_input/bsn_vlan_counter
@@ -34,7 +34,7 @@
     OFP_BSN_VLAN_ALL = 0xffff,
 };
 
-enum of_bsn_vlan_counter(wire_type=uint8_t, complete=False) {
+enum of_bsn_vlan_counter(wire_type=uint8_t, complete=False, stable=True) {
   OFP_BSN_VLAN_COUNTER_RX_BYTES = 0,
   OFP_BSN_VLAN_COUNTER_RX_PACKETS = 1,
   OFP_BSN_VLAN_COUNTER_TX_BYTES = 2,
diff --git a/openflow_input/bsn_vrf_counter b/openflow_input/bsn_vrf_counter
index 5244eab..b638ff7 100644
--- a/openflow_input/bsn_vrf_counter
+++ b/openflow_input/bsn_vrf_counter
@@ -34,7 +34,7 @@
     OFP_BSN_VRF_ALL = 0xffffffff,
 };
 
-enum of_bsn_vrf_counter(wire_type=uint8_t, complete=False) {
+enum of_bsn_vrf_counter(wire_type=uint8_t, complete=False, stable=True) {
   OFP_BSN_VRF_COUNTER_BYTES = 0,
   OFP_BSN_VRF_COUNTER_PACKETS = 1,
 };