Ethereal转储中TSV和TSER字段的含义是什么？

Question

Ethereal转储中TSV和TSER字段的含义是什么？我尝试了谷歌搜索，但无法找到答案。

Answer 1

TSV是Timestamp Value字段。它与序号一起使用来唯一标识段（因为序号可能会换行）。

TSER是Timestamp Echo Reply字段。这用于ACK消息。它包含收到的最后一个TSV值的副本。它可用于往返时间估算（RTT =当前时间 - TSER）。

中的字段在RFC 1323 (TCP Extensions for High Performance)正式地描述：

TCP Timestamps Option (TSopt): 

    Kind: 8 

    Length: 10 bytes 

     +-------+-------+---------------------+---------------------+ 
     |Kind=8 | 10 | TS Value (TSval) |TS Echo Reply (TSecr)| 
     +-------+-------+---------------------+---------------------+ 
      1  1    4      4 

    The Timestamps option carries two four-byte timestamp fields. 
    The Timestamp Value field (TSval) contains the current value of 
    the timestamp clock of the TCP sending the option. 

    The Timestamp Echo Reply field (TSecr) is only valid if the ACK 
    bit is set in the TCP header; if it is valid, it echos a times- 
    tamp value that was sent by the remote TCP in the TSval field 
    of a Timestamps option. When TSecr is not valid, its value 
    must be zero. The TSecr value will generally be from the most 
    recent Timestamp option that was received; however, there are 
    exceptions that are explained below.