diff --git a/protocols/sacn/source.h b/protocols/sacn/source.h
index e33788e..8882b79 100644
--- a/protocols/sacn/source.h
+++ b/protocols/sacn/source.h
@@ -54,6 +54,16 @@ protected:
 
 private:
     std::unordered_map <uint16_t, Universe *> universes_;
+
+    /// > \cite sACN 6.2.5 E1.31 Data Packet: Sequence Number
+    /// >
+    /// > Sources shall maintain a sequence for each universe they transmit.
+    /// > The sequence number for a universe shall be incremented by one for
+    /// > every packet sent on that universe. There is no implied relationship
+    /// > between the sequence number of an E1.31 Synchronization Packet and
+    /// > the sequence number of an E1.31 Data Packet on that same universe.
+    std::unordered_map <uint16_t, uint8_t> data_sequences_;
+    std::unordered_map <uint16_t, uint8_t> sync_sequences_;
 };