diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index ebc28306c..e73047c90 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1615,6 +1615,16 @@
 #define MBEDTLS_SSL_FREE_SERVER_CERTIFICATE
 
 
+/**
+ * \def MBEDTLS_IMMEDIATE_TRANSMISSION
+ *
+ * Force stack to immediately transmit messages.
+ *
+ * Requires: MBEDTLS_SSL_PROTO_DTLS
+ */
+#define MBEDTLS_IMMEDIATE_TRANSMISSION
+
+
 /**
  * \def MBEDTLS_SSL_HW_RECORD_ACCEL
  *