When not configured in rtconfig.h, lwipopt.h will give us a reasonable value(TCP_MSS * 2).
@@ -113,9 +113,6 @@
/* the number of simulatenously active TCP connections*/
#define RT_LWIP_TCP_PCB_NUM 5
-/* TCP sender buffer space*/
-#define RT_LWIP_TCP_SND_BUF 1500
-
/* Enable SNMP protocol*/
/* #define RT_LWIP_SNMP */
Grissiom