Yeah I think it is localized. Network paths have been quite variable for me. Every once in a while I start getting massive delays from the NIST servers to my system, resulting in results like yours.
Interestingly though, time-e-g was one of the only servers that didn't have this problem for me. This is a recent wedge plot for it. seems to be working fine for me now, just with a variable outgoing delay causing positive offsets, which seems to be more of a problem with my connection than anything else. On Tue, Dec 14, 2021 at 9:04 PM K5ROE Mike <[email protected]> wrote: > On 12/14/21 5:23 PM, Hal Murray wrote: > > > >> Out of curiosity, since you monitor NIST Gaithersburg, if you were to > average > >> over the offsets for a whole month, what kind of value would you get? > Surely > >> it is close to zero but I am curious how close. Within 1ms? > > > > It depends. Mostly on the routing between you and NIST. If you are > closer, > > the routing is more likely to be symmetric. > > > > From my experience, routing is generally stable on the scale of > months. There > > are short (hours) changes when a fiber gets cut or a router gets busted. > > There are long term changes as people add fibers and/or change business > deals. > > > > There are some cases where a stable routing will produce 2 answers: x% > of the > > packets will be slightly faster/slower than most of them. I think what's > > going on is that the routers are doing load sharing on multiple paths, > hashing > > on the address+port. Or something like that. So it's a roll of the dice > > which path you get. > > > > -------- > > > > I'm in California. > > > > NIST has NTP servers at 3 locations in the Boulder CO area: NIST, WWV, > and > > Univ of Colorado. (Google maps says WWV is 60 miles north of Bouler. > Univ of > > Colorado is a few miles from NIST.) > > > > From a cheap cloud server (Digital Ocean) in San Francisco, the RTT to > NIST is > > 31.5 ms, to WWV is 32.1 ms, to Univ of Colorado is 54.5 ms. The time > offsets > > are about 1 ms for NIST and WWV and 12 ms for Univ of Colorado. > > > > From my home (AT&T via Sonic), 30 miles south of San Francisco, the > RTTs are > > 61 ms for NIST and WWV and 81-82 for Univ of Colorado. Offsets are 6-7 > ms for > > NIST and WWV and 4-5 ms in the other direction for Univ of Colorado. > > > > > > Might be a localized routing phenomenon. Using my verizon connection from > Northern Virginia the results are awful for time-e-g.nist.gov: > > remote refid st t when poll reach delay offset > jitter > > ============================================================================== > -192.168.1.219 68.69.221.61 2 u 56 64 377 0.400 -0.290 > 0.035 > *192.168.1.224 .PPS. 1 u 1 16 377 0.184 0.087 > 0.017 > -129.6.15.26 .NIST. 1 u 32 64 377 93.087 -37.940 > 7.867 > > However from my AWS machine in Oregon: > > MS Name/IP address Stratum Poll Reach LastRx Last sample > > =============================================================================== > ^- 152.63.13.177 3 6 377 63 -2011us[-2011us] +/- > 128ms > ^+ 209.182.153.6 2 7 377 65 -959us[ -959us] +/- > 86ms > ^- 64.139.66.105 3 6 377 128 -5838us[-5838us] +/- > 134ms > ^+ 129.6.15.26 1 6 377 64 -2075us[-2075us] +/- > 37ms > ^* 173.66.105.50 1 8 377 438 -448us[ -870us] +/- > 38ms > > > -mike > _______________________________________________ > time-nuts mailing list -- [email protected] -- To unsubscribe send > an email to [email protected] > To unsubscribe, go to and follow the instructions there. >
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