最近在做ppp协议，对其FSC校验不是很了解，查找了资料也很片面，经过慢慢查找，终于总结出了基本过程，于是写了个控制台程序来测试了一下，数据都正确通过。（注：为了减小文件大小，Debug生成的临时文件已全部删除，请重新生成）-Ppp agreement recently made its FSC parity is not very understanding , finding the information is also very one-sided , after slowly find