diff --git a/astlpc.c b/astlpc.c
index 7ab78d6..de3982c 100644
--- a/astlpc.c
+++ b/astlpc.c
@@ -356,7 +356,7 @@
 	astlpc->binding.version = 1;
 	astlpc->binding.tx = mctp_binding_astlpc_tx;
 	astlpc->binding.start = mctp_binding_astlpc_start;
-	astlpc->binding.pkt_size = MCTP_BMTU;
+	astlpc->binding.pkt_size = MCTP_PACKET_SIZE(MCTP_BTU);
 	astlpc->binding.pkt_pad = 0;
 	astlpc->lpc_map = NULL;
 
diff --git a/libmctp.h b/libmctp.h
index b36a943..69ec46a 100644
--- a/libmctp.h
+++ b/libmctp.h
@@ -31,9 +31,9 @@
 #define MCTP_HDR_TAG_SHIFT	(0)
 #define MCTP_HDR_TAG_MASK	(0x7)
 
-/* Baseline maximum size of a MCTP packet */
-#define MCTP_BMTU_PAYLOAD	64
-#define MCTP_BMTU		(MCTP_BMTU_PAYLOAD + sizeof(struct mctp_hdr))
+/* Baseline Transmission Unit and packet size */
+#define MCTP_BTU		64
+#define MCTP_PACKET_SIZE(unit)	((unit) + sizeof(struct mctp_hdr))
 
 /* packet buffers */
 
diff --git a/serial.c b/serial.c
index 808c215..c90de54 100644
--- a/serial.c
+++ b/serial.c
@@ -347,7 +347,7 @@
 	serial->rx_pkt = NULL;
 	serial->binding.name = "serial";
 	serial->binding.version = 1;
-	serial->binding.pkt_size = MCTP_BMTU;
+	serial->binding.pkt_size = MCTP_PACKET_SIZE(MCTP_BTU);
 	serial->binding.pkt_pad = 0;
 
 	serial->binding.start = mctp_serial_core_start;
diff --git a/tests/test-utils.c b/tests/test-utils.c
index dc0a5f3..df04343 100644
--- a/tests/test-utils.c
+++ b/tests/test-utils.c
@@ -27,7 +27,7 @@
 	test->binding.name = "test";
 	test->binding.version = 1;
 	test->binding.tx = mctp_binding_test_tx;
-	test->binding.pkt_size = MCTP_BMTU;
+	test->binding.pkt_size = MCTP_PACKET_SIZE(MCTP_BTU);
 	test->binding.pkt_pad = 0;
 	return test;
 }
diff --git a/tests/test_bridge.c b/tests/test_bridge.c
index 496ae19..43b5d76 100644
--- a/tests/test_bridge.c
+++ b/tests/test_bridge.c
@@ -68,7 +68,7 @@
 	binding->binding.name = "test";
 	binding->binding.version = 1;
 	binding->binding.tx = mctp_binding_bridge_tx;
-	binding->binding.pkt_size = MCTP_BMTU;
+	binding->binding.pkt_size = MCTP_PACKET_SIZE(MCTP_BTU);
 	binding->binding.pkt_pad = 0;
 	return binding;
 }