LwIP是Light Weight (轻型)IP协议，有无操作系统的支持都可以运行。LwIP实现的重点是在保持TCP协议主要功能的基础上减少对RAM 的占用，它只需十几KB的RAM和40K左右的ROM就可以运行。本代码是对LWIP的移植-LwIP is Light Weight (light) IP protocol, with or without the support of the operating system can run. Key LwIP achieve it is to re