问题
问答题 简答题
DL层功能：
答案
参考答案：
比特流被组织成数据链路协议数据单元，并以帧为单位传输，帧中包含地址、控制、数据及校验码等信息。主要作用是是通过校验、确认和反馈重发等手段，将不可靠的物理链路改造成对网络层来说是无差错的数据链路。流量控制。
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DL层功能：
参考答案：
比特流被组织成数据链路协议数据单元，并以帧为单位传输，帧中包含地址、控制、数据及校验码等信息。主要作用是是通过校验、确认和反馈重发等手段，将不可靠的物理链路改造成对网络层来说是无差错的数据链路。流量控制。
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| Jerry is from Australia(澳大利亚). He is fourteen. He is a student in No. 2 Middle School. He doesn't like 1 . He doesn't like some of his subjects. He thinks they are 2 . He often 3 to school late(迟的). When his teachers ask him 4 he is late, he often says he has lots of things to do at home. We tell Jerry not to do so, 5 he doesn't listen to 6 . 7 class, Jerry doesn't play sports with us. He wants 8 early(早). Jerry likes English and music. He can 9 many English songs. And he sings very well. We all like to listen to him. He wants to be a musician. Jerry's father thinks he should(应该) learn all of his subjects well, but his mother thinks Jerry can only do what he wants to do. 10 you help Jerry and his parents? | ||||
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