[ntp:questions] why do internet servers not poll atlonger intervals
David J Taylor
david-taylor at blueyonder.co.uk.invalid
Wed Feb 15 09:20:27 UTC 2012
> My PC connects to my basement router with wifi G, which is then wired to
> a wired router which is wired to the cable modem. Service is Comcast
> 16-20 Mbps down and 3-4 Mbps up. I get pretty low jitter to the NY NIST
> server, which is the one this machine normally hits if there is no GPS.
> I'm not sure if Comcast has a public NTP server or not.
>
> Sincerely,
>
> Ron
So that's a Wi-Fi connection, plus a second router, Ron. Not so direct.
I'm still slightly surprised at the long delays, and wonder how heavily
loaded with your own connection, or the lines provided by your ISP
actually are.
I wonder about:
- making your basement box into an access point rather than router. [I
have that arrangement here, but I've never compared the delays or jitter
comparing one approach to the other.]
- whether the cable modem or your own wired router can provide one
additional NTP server?
Aside: I use DD-WRT on my own router, which does have an NTP client but
not server. I use that firmware as I can then use SNMP functions to
interrogate the router and plot the results with MRTG:
DD-WRT:
http://www.dd-wrt.com
Some router parameters:
http://www.satsignal.eu/mrtg/performance_cable-modem.php
Apparently, Comcast did have some NTP servers back in 2006:
http://lists.netisland.net/archives/plug/plug-2006-02/msg00082.html
The router next upstream, or next but one, from your premises may be worth
checking for NTP. Sometimes these devices will provide an NTP service
even though they don't response to and "ntpq -p". I would just add one to
your existing configuration to see how good or otherwise it is.
Cheers,
David
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