diff --git a/py_gen/templates/instruction.py b/py_gen/templates/instruction.py
index 978e38b..b3957cc 100644
--- a/py_gen/templates/instruction.py
+++ b/py_gen/templates/instruction.py
@@ -54,16 +54,42 @@
 
 :: #endfor
 
+def parse_experimenter(reader):
+    experimenter, = reader.peek("!4xL")
+    if experimenter == 0x005c16c7: # Big Switch Networks
+        subtype, = reader.peek("!8xL")
+    else:
+        raise loxi.ProtocolError("unexpected experimenter id %#x" % experimenter)
+
+    if subtype in experimenter_parsers[experimenter]:
+        return experimenter_parsers[experimenter][subtype](reader)
+    else:
+        raise loxi.ProtocolError("unexpected experimenter id %#x subtype %#x" % (experimenter, subtype))
+
 parsers = {
 :: sort_key = lambda x: x.type_members[0].value
 :: msgtype_groups = itertools.groupby(sorted(ofclasses, key=sort_key), sort_key)
 :: for (k, v) in msgtype_groups:
 :: k = util.constant_for_value(version, "ofp_instruction_type", k)
 :: v = list(v)
-:: if len(v) == 1:
+:: if len(v) == 1 or k == 0xffff:
     ${k} : ${v[0].pyname}.unpack,
 :: else:
     ${k} : parse_${k[12:].lower()},
 :: #endif
 :: #endfor
 }
+
+:: experimenter_ofclasses = [x for x in ofclasses if x.type_members[0].value == 0xffff]
+:: sort_key = lambda x: x.type_members[1].value
+:: experimenter_ofclasses.sort(key=sort_key)
+:: grouped = itertools.groupby(experimenter_ofclasses, sort_key)
+experimenter_parsers = {
+:: for (experimenter, v) in grouped:
+    ${experimenter} : {
+:: for ofclass in v:
+        ${ofclass.type_members[2].value}: ${ofclass.pyname}.unpack,
+:: #endfor
+    },
+:: #endfor
+}