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:[email protected]] On Behalf Of William Unruh Sent: Tuesday, June 8, 2021 3:50 AM To: [email protected] 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 <[email protected]> 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 [email protected] http://lists.ntp.org/listinfo/questions _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
