Ethereal轉儲中TSV和TSER字段的含義是什麼？

Question

Ethereal轉儲中TSV和TSER字段的含義是什麼？我嘗試了谷歌搜索，但無法找到答案。

Answer 1

TSV是Timestamp Value字段。它與序號一起使用來唯一標識段（因爲序號可能會換行）。

TSER是Timestamp Echo Reply字段。這用於ACK消息。它包含收到的最後一個TSV值的副本。它可用於往返時間估算（RTT =當前時間 - 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.