题目内容
在计算机局域网协议集中，数据链路层又可分为介质访问控制子层和 (52) ：LAN参考模型中服务访问点SAP的作用是 (53) ；局域网中数据传输的误码率较低，一般约在 (54) ；在LAN的介质访问方式中，争用属于 (55) ；以太网的介质访问控制方式与CSMA相比较，其所做的改进是 (56) 。
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在计算机局域网协议集中，数据链路层又可分为介质访问控制子层和 (52) ：LAN参考模型中服务访问点SAP的作用是 (53) ；局域网中数据传输的误码率较低，一般约在 (54) ；在LAN的介质访问方式中，争用属于 (55) ；以太网的介质访问控制方式与CSMA相比较，其所做的改进是 (56) 。
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