[ntp:questions] Win7: ntpd adjusting time backwards
david-taylor at blueyonder.co.uk.invalid
Tue Dec 11 19:58:38 UTC 2012
On 11/12/2012 19:35, Rick Jones wrote:
> David Taylor <david-taylor at blueyonder.co.uk.invalid> wrote:
>> What happens if the link to the Internet is rather asymmetrical? For
>> example, here I am stuck with 30 Mb/s down, but only 3 Mb/s up.
> Handwaving a bit... The query and the response seem to be something
> like 90 bytes (including an Ethernet header). That then is 720 bits.
> At 3 Mbits/s that would be 0.24 milliseconds of transmit time. It
> would then be 0.024 milliseconds on the downlink. I suspect that
> asymmetry is dwarfed by either queueing delays (bufferbloat) when
> either/both are active and/or the rest of the delays from your system
> to the server(s).
> rick jones
Yes, I see what you mean, but I was thinking of the whole network, and
not simply the up and down speeds. That we have a 10:1 ratio may
suggest how the rest of that ISP's network is configured. The delays in
the cable modem, Samknows box, router and 1 Gb/s switch are likely to be
far in excess of the 0.024 ms and even the 0.24 ms!
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