南海凝心计算机网络第四版习题答案(中文版)
4-22 An IP packet to be transmitted by Ethernet is 60 bytes long, including all its headers. If LLC is not in use, is padding needed in the Ethernet frame, and if so, how many bytes?
一个通过以太网传送到IP分组有60字节长，其中包括所有的头部。如果没有使用LLC的话，则以太网帧中需要填补字节码？如果需要的话，请问需要填补多少字节？
最小的以太帧是64bytes，包括了以太帧头部的二者地址、类型/长度域、校验和。因为头部域占用18 bytes 报文是60 bytes，总的帧长度是78 bytes, 已经超过了64-byte 的最小限制。因此，不需要填补。
4-23 Ethernet frames must be at least 64 bytes long to ensure that the transmitter is still going in the event of a collision at the far end of the cable. Fast Ethernet has the same 64-byte minimum frame size but can get the bits out ten times faster. How is it possible to maintain the same minimum
