diff --git a/protocol.py b/protocol.py
new file mode 100644
index 0000000..83c6e0f
--- /dev/null
+++ b/protocol.py
@@ -0,0 +1,12 @@
+import struct
+
+TYPE_DATA = 0
+TYPE_ACK = 1
+
+def make_packet(seq, ptype, payload=b""):
+    return struct.pack("BB", seq, ptype) + payload
+
+def parse_packet(packet):
+    seq, ptype = struct.unpack("BB", packet[:2])
+    payload = packet[2:]
+    return seq, ptype, payload