diff --git a/lib/includes/ngtcp2/ngtcp2.h b/lib/includes/ngtcp2/ngtcp2.h
index c4bbbc8d707491b3c06202e27f5cf484eea59720..a8611e4af64cbf92de94c56dfbd8fad90ac1aa34 100644
--- a/lib/includes/ngtcp2/ngtcp2.h
+++ b/lib/includes/ngtcp2/ngtcp2.h
@@ -447,7 +447,11 @@ typedef enum ngtcp2_rand_ctx {
   NGTCP2_RAND_CTX_PATH_CHALLENGE
 } ngtcp2_rand_ctx;
 
-#define NGTCP2_MAX_PKT_SIZE 65527
+/*
+ * NGTCP2_DEFAULT_MAX_UDP_PAYLOAD_SIZE is the default value of
+ * max_udp_payload_size transport parameter.
+ */
+#define NGTCP2_DEFAULT_MAX_UDP_PAYLOAD_SIZE 65527
 
 /**
  * @macro
@@ -3001,7 +3005,7 @@ NGTCP2_EXTERN void ngtcp2_path_storage_zero(ngtcp2_path_storage *ps);
  * default value to the following fields:
  *
  * * cc_algo = NGTCP2_CC_ALGO_CUBIC
- * * transport_params.max_udp_payload_size = NGTCP2_MAX_PKT_SIZE
+ * * transport_params.max_udp_payload_size = NGTCP2_DEFAULT_MAX_UDP_PAYLOAD_SIZE
  * * transport_params.ack_delay_component = NGTCP2_DEFAULT_ACK_DELAY_EXPONENT
  * * transport_params.max_ack_delay = NGTCP2_DEFAULT_MAX_ACK_DELAY
  * * transport_params.active_connection_id_limit =
diff --git a/lib/ngtcp2_conn.c b/lib/ngtcp2_conn.c
index c7466333dfef2d545af56d6fe4e616774048917b..4b50540be0fe617727ce628b8c6a1feb0d986769 100644
--- a/lib/ngtcp2_conn.c
+++ b/lib/ngtcp2_conn.c
@@ -9469,7 +9469,8 @@ void ngtcp2_path_challenge_entry_init(ngtcp2_path_challenge_entry *pcent,
 void ngtcp2_settings_default(ngtcp2_settings *settings) {
   memset(settings, 0, sizeof(*settings));
   settings->cc_algo = NGTCP2_CC_ALGO_CUBIC;
-  settings->transport_params.max_udp_payload_size = NGTCP2_MAX_PKT_SIZE;
+  settings->transport_params.max_udp_payload_size =
+      NGTCP2_DEFAULT_MAX_UDP_PAYLOAD_SIZE;
   settings->transport_params.ack_delay_exponent =
       NGTCP2_DEFAULT_ACK_DELAY_EXPONENT;
   settings->transport_params.max_ack_delay = NGTCP2_DEFAULT_MAX_ACK_DELAY;
diff --git a/lib/ngtcp2_crypto.c b/lib/ngtcp2_crypto.c
index 20d47d4f8f399aaf16e619c3c36a85a9d4345dfe..c1339cb3d14a6d00348e2e2268bc0a379a0062f1 100644
--- a/lib/ngtcp2_crypto.c
+++ b/lib/ngtcp2_crypto.c
@@ -217,7 +217,7 @@ ngtcp2_encode_transport_params(uint8_t *dest, size_t destlen,
     len += varint_paramlen(NGTCP2_TRANSPORT_PARAM_INITIAL_MAX_STREAMS_UNI,
                            params->initial_max_streams_uni);
   }
-  if (params->max_udp_payload_size != NGTCP2_MAX_PKT_SIZE) {
+  if (params->max_udp_payload_size != NGTCP2_DEFAULT_MAX_UDP_PAYLOAD_SIZE) {
     len += varint_paramlen(NGTCP2_TRANSPORT_PARAM_MAX_UDP_PAYLOAD_SIZE,
                            params->max_udp_payload_size);
   }
@@ -325,7 +325,7 @@ ngtcp2_encode_transport_params(uint8_t *dest, size_t destlen,
                            params->initial_max_streams_uni);
   }
 
-  if (params->max_udp_payload_size != NGTCP2_MAX_PKT_SIZE) {
+  if (params->max_udp_payload_size != NGTCP2_DEFAULT_MAX_UDP_PAYLOAD_SIZE) {
     p = write_varint_param(p, NGTCP2_TRANSPORT_PARAM_MAX_UDP_PAYLOAD_SIZE,
                            params->max_udp_payload_size);
   }
@@ -477,7 +477,7 @@ int ngtcp2_decode_transport_params(ngtcp2_transport_params *params,
   params->initial_max_stream_data_bidi_local = 0;
   params->initial_max_stream_data_bidi_remote = 0;
   params->initial_max_stream_data_uni = 0;
-  params->max_udp_payload_size = NGTCP2_MAX_PKT_SIZE;
+  params->max_udp_payload_size = NGTCP2_DEFAULT_MAX_UDP_PAYLOAD_SIZE;
   params->ack_delay_exponent = NGTCP2_DEFAULT_ACK_DELAY_EXPONENT;
   params->stateless_reset_token_present = 0;
   params->preferred_address_present = 0;
diff --git a/tests/ngtcp2_crypto_test.c b/tests/ngtcp2_crypto_test.c
index 63d44ac5545160015a9a184b2533f521abec6510..a5a8820cfea0df6f119f9ab46b39bd8d1b225651 100644
--- a/tests/ngtcp2_crypto_test.c
+++ b/tests/ngtcp2_crypto_test.c
@@ -52,7 +52,7 @@ void test_ngtcp2_encode_transport_params(void) {
   memset(&nparams, 0, sizeof(nparams));
 
   /* CH, required parameters only */
-  params.max_udp_payload_size = NGTCP2_MAX_PKT_SIZE;
+  params.max_udp_payload_size = NGTCP2_DEFAULT_MAX_UDP_PAYLOAD_SIZE;
   params.ack_delay_exponent = NGTCP2_DEFAULT_ACK_DELAY_EXPONENT;
   params.max_ack_delay = NGTCP2_DEFAULT_MAX_ACK_DELAY;
   params.initial_scid = scid;
@@ -95,7 +95,7 @@ void test_ngtcp2_encode_transport_params(void) {
   memset(&nparams, 0, sizeof(nparams));
 
   /* EE, required parameters only */
-  params.max_udp_payload_size = NGTCP2_MAX_PKT_SIZE;
+  params.max_udp_payload_size = NGTCP2_DEFAULT_MAX_UDP_PAYLOAD_SIZE;
   params.ack_delay_exponent = NGTCP2_DEFAULT_ACK_DELAY_EXPONENT;
   params.max_ack_delay = NGTCP2_DEFAULT_MAX_ACK_DELAY;
   params.original_dcid = dcid;