学过分布式系统的进来

tempzoe

A client attempts to synchronize with a time server. It records the round-trip times and timestamps returned by
the server in the table below.
Which of these times should it use to set its clock? To what time should it set it? Estimate the accuracy of the
setting with respect to the server’s clock. If it is known that the time between sending and receiving a message
in the system concerned is at least 8 ms, do your answers change?
Round-trip (ms) Time (hr:min:sec)
22                    10:54:23.674
25                    10:54:25.450
20                    10:54:28.342

前面的问题都知道,最后一个问题是If it is known that the time between sending and receiving a message in the system conerne is at least 14ms. how do you answer change?
这个还能用Christian算法吗？到底怎么计算?

(Y)

由于信息有限，不知道你说的这个是对现有的PTP协议进行解答。还是进一步进行修正来提高精度。
还有一些默认的信息没有写出来，比如，问题是指一级时钟同步过程，而且延时是ms级，那么应该是普通级别的同步。
如果是为了解题，那可以简单的用时间戳平均值及延时平均值来修正。最后一个变为14ms的，把平均值重新算一下就可以了。

高精度时钟同步可以参见IEEE1588的方法。可以达到0.1微妙级的精度。