diff --git a/transmit_disfection_protocol.hpp b/transmit_disfection_protocol.hpp
index a47fcfa..745c629 100644
--- a/transmit_disfection_protocol.hpp
+++ b/transmit_disfection_protocol.hpp
@@ -16,6 +16,8 @@ namespace transmit_disfection_protocol {
  *
  */
 
+#define MAX_PACKET_LEN 120
+
 #define PROTOCOL_VERSION 7
 #define HEART_OVERTIME   (30 * 1000)
 #define SWITCH_CASE_STR(key) \