diff --git a/src/python/loxi/of13/action.py b/src/python/loxi/of13/action.py
index aebe510..d99ff1b 100644
--- a/src/python/loxi/of13/action.py
+++ b/src/python/loxi/of13/action.py
@@ -190,6 +190,61 @@
 
 experimenter.subtypes[6035143] = bsn
 
+class bsn_checksum(bsn):
+    type = 65535
+    experimenter = 6035143
+    subtype = 4
+
+    def __init__(self, checksum=None):
+        if checksum != None:
+            self.checksum = checksum
+        else:
+            self.checksum = 0
+        return
+
+    def pack(self):
+        packed = []
+        packed.append(struct.pack("!H", self.type))
+        packed.append(struct.pack("!H", 0)) # placeholder for len at index 1
+        packed.append(struct.pack("!L", self.experimenter))
+        packed.append(struct.pack("!L", self.subtype))
+        packed.append(util.pack_checksum_128(self.checksum))
+        length = sum([len(x) for x in packed])
+        packed[1] = struct.pack("!H", length)
+        return ''.join(packed)
+
+    @staticmethod
+    def unpack(reader):
+        obj = bsn_checksum()
+        _type = reader.read("!H")[0]
+        assert(_type == 65535)
+        _len = reader.read("!H")[0]
+        orig_reader = reader
+        reader = orig_reader.slice(_len - (2 + 2))
+        _experimenter = reader.read("!L")[0]
+        assert(_experimenter == 6035143)
+        _subtype = reader.read("!L")[0]
+        assert(_subtype == 4)
+        obj.checksum = util.unpack_checksum_128(reader)
+        return obj
+
+    def __eq__(self, other):
+        if type(self) != type(other): return False
+        if self.checksum != other.checksum: return False
+        return True
+
+    def pretty_print(self, q):
+        q.text("bsn_checksum {")
+        with q.group():
+            with q.indent(2):
+                q.breakable()
+                q.text("checksum = ");
+                q.pp(self.checksum)
+            q.breakable()
+        q.text('}')
+
+bsn.subtypes[4] = bsn_checksum
+
 class bsn_mirror(bsn):
     type = 65535
     experimenter = 6035143