diff --git a/py_gen/oftype.py b/py_gen/oftype.py
index 40bcb40..7e28a0c 100644
--- a/py_gen/oftype.py
+++ b/py_gen/oftype.py
@@ -111,6 +111,11 @@
         init='None',
         pack='%s.pack()',
         unpack='oxm.oxm.unpack(%s)'),
+
+    'of_checksum_128_t': OFTypeData(
+        init='0',
+        pack='util.pack_checksum_128(%s)',
+        unpack="util.unpack_checksum_128(%s)"),
 }
 
 ## Fixed length strings
diff --git a/py_gen/templates/util.py b/py_gen/templates/util.py
index ed2698a..d690939 100644
--- a/py_gen/templates/util.py
+++ b/py_gen/templates/util.py
@@ -182,3 +182,10 @@
         except loxi.ProtocolError:
             return None
     return [x for x in loxi.generic_util.unpack_list(reader, deserializer) if x != None]
+
+def pack_checksum_128(value):
+    return struct.pack("!QQ", (value >> 64) & MASK64, value & MASK64)
+
+def unpack_checksum_128(reader):
+    hi, lo = reader.read("!QQ")
+    return (hi << 64) | lo