[ntp:questions] Score is low and not raising

Charles Elliott elliott.ch at comcast.net
Tue Jun 8 11:49:14 UTC 2021


Is your Internet connection asymmetric?  Most cable and DSL (ADSL)
connections are asymmetric with much less speed upstream than downstream.
This severely affects the accuracy of NTPD because, essentially, the time
offset between client and server is measured by the difference between the
packet times to and from the server.  If your Internet connection is
asymmetric, then the time you dispense will always be in error proportional
to the difference between your upstream and downstream speeds.  See RFC 5905
- Network Time Protocol Version 4 Protocol and Algorithms Specification.htm
for the actual formulas; search for "delay" and/or "offset" to find the
equations in T1, T2, T3, and T4, which are the measured times.

Charles Elliott 

-----Original Message-----
From: questions
[mailto:questions-bounces+elliott.ch=comcast.net at lists.ntp.org] On Behalf Of
William Unruh
Sent: Tuesday, June 8, 2021 3:50 AM
To: questions at lists.ntp.org
Subject: Re: [ntp:questions] Score is low and not raising

You give no details at all so it is hard to figure out what you are doing
never mind what is wrong. It seems you have a 500 ms (1/2 second) offset,
which really is pretty terrible. Wrong edge on the interrupt? 
( and at the end it inexplicably drops to 100ms, which is still pretty
terrible but better-- what changed) 

Hook you Pis up to the network, and compare your PPS yourself to some pool
server. That way you can debug yourself instead of others doing it for you. 


On 2021-06-08, ProGeek <progeekro at gmail.com> wrote:
> Hello,
> i have 2 IPv6 servers made publicly some days ago.
> Servers are build around Raspberry PI and U-blox GPS modules, using PPS
and GPIO.
> The problem is that i try to make the servers available in pool, but i get
constant -20 on rating.
>
> Any idea how can i improve the score?
>  
> https://www.ntppool.org/scores/2a02:2f04:a0e:9199:99::2
>
> https://www.ntppool.org/scores/2a02:2f04:a0e:9199:99::2

_______________________________________________
questions mailing list
questions at lists.ntp.org
http://lists.ntp.org/listinfo/questions



More information about the questions mailing list