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本帖最后由 goingstudy 于 2017-06-28 20:29 编辑
在RFC 6582NewReno 中的“Handling Duplicate Acknowledgments after a timeout" section 里:
After each retransmit timeout, the highest sequence number
transmitted so far is recorded in the variable recover. If, after a
retransmit timeout, the TCP data sender retransmits three consecutive
packets that have already been received by the data receiver, then
the TCP data sender will receive three duplicate acknowledgments that
do not cover more than recover. In this case, the duplicate
acknowledgments are not an indication of a new instance of
congestion. They are simply an indication that the sender has
unnecessarily retransmitted at least three packets.
有几个问题不明白:
1. 为什么timeout 后会重传3个连续的包,不是应该重传一个吗?我在其他有地方的文档里好像看到说一般会在timeou后重传多个,这个谁能确定的解释一下吗?
2.收到的3个dup ack 为什么不会包含‘recover’, 按我的理解肯定会包含,这个怎么解释?
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