计算机英语习题
PPPwasclearlydesignedtobeimplementedinsoftware,notinhardwareasHDLCnearlyalwaysis.Withasoftwareimplementation,workingentirelywithbytesismuchsimplerthanworkingwithindividualbits.Inaddition,PPPwasdesignedtobeusedwithmodems,andmodemsacceptandtransmitdatainunitsof1byte,not1bit.
这个答案原题是:PPP基本上以HDLC为基础.HDLC使用了位填充技术来防止在净荷数据中偶尔出现标志字节,以避免混淆.请给一个理由说明为什么PPP却使用了字节填充技术!