#ptp — Public Fediverse posts

‘Filmmaker’ Who Sued PTP, BTN, and Four Other Private Torrent Trackers May Be an Impostor

https://torrentfreak.com/filmmaker-who-sued-ptp-btn-and-four-other-private-torrent-trackers-may-be-an-impostor/

#AppsandSites #Lawsuits #piracy #btn #ptp

Pointe-à-Pitre Le Raizet International Airport - Pointe-à-Pitre, Guadeloupe

https://en.wikipedia.org/wiki/Pointe-%C3%A0-Pitre_International_Airport
https://www.openstreetmap.org/#map=13/16.265301/-61.531799

#TFFR #PTP #PointeàPitre #Guadeloupe #airport #aviation #avgeeks #GIS

Когда Ethernet обманывает логику отказоустойчивости

Отказоустойчивость в промышленном Ethernet не всегда означает предсказуемость. Даже при рабочем резервировании асимметрия задержек может сбить синхронизацию, исказить расчеты PTP и привести к ошибкам в управлении. Разбираем, откуда берется эта проблема и как учитывать ее при проектировании сети.

https://habr.com/ru/companies/otus/articles/1052374/

#промышленный_Ethernet #отказоустойчивость #асимметрия_задержек #PTP #IEEE_1588 #сетевые_задержки #резервирование_сети #MRP #RSTP #проектирование_сети

Pointe-à-Pitre Le Raizet International Airport - Pointe-à-Pitre, Guadeloupe

https://en.wikipedia.org/wiki/Pointe-%C3%A0-Pitre_International_Airport
https://www.openstreetmap.org/#map=13/16.265301/-61.531799

#TFFR #PTP #PointeàPitre #Guadeloupe #airport #aviation #avgeeks #GIS

Tomorrow is the most productive day of the week.

That is because you are going to Push To Production.

#PTP

[Перевод] Синхронизация часов — это кошмар

Кажется, что время — это просто. Но мы, инженеры, теряем сон из-за такой простой задачи, как синхронизация часов. Причина этого в том, что не существует каких-то глобальных часов. У нас есть тысячи машин, распределённых по дата-центрам, континентам и часовым поясам; каждая из них работает независимо от других, поэтому ответ на простой вопрос «сколько сейчас времени?» оказывается на удивление сложным. Синхронизация часов становится основой самых сложных задач в распределённых системах, она влияет на всё, от согласованности баз данных и отладки до финансовых транзакций.

https://habr.com/ru/companies/ruvds/articles/1030464/

#синхронизация_времени #ntp #ptp #атомные_часы #ruvds_перевод

Blogged: My public NTP Server, one year later: Hardware upgrades, better RF, and OSNMA

https://www.tabsoverspaces.com/id/233969

#time #ntp #cm4 #raspberrypi #ptp

Aviation weather for Pointe-à-Pitre Le Raizet airport (Guadeloupe) is “TFFR 161300Z AUTO 10018KT 9999 FEW036 28/19 Q1019 TEMPO 09018G28KT” : See what it means on https://www.bigorre.org/aero/meteo/tffr/en #pointeapitreleraizetairport #airport #pointeapitre #guadeloupe #tffr #ptp #metar #aviation #aviationweather #avgeek vl

As well as the obvious implications to navigation both at sea and in the air, this is a timely reminder not to rely only on satellite-based signals for network time synchronisation.

#GPS #GNSS #jamming #NTP #PTP #time

https://www.france24.com/en/middle-east/20260306-surge-gps-interference-strait-hormuz-increases-shipping-risks

TIL: Besides UTC, there also is TAI – Temps Atomics International aka International Atomic Time. And well … TAI currently is UTC +37s 🤯

For other interesting things about time, computer time and time protocols, I highly recommend the talk on PTP from last years #39C3: https://media.ccc.de/v/39c3-excuse-me-what-precise-time-is-it #ptp #ntp #timeprotocol

🚂🤖 Eurostar's #AI #chatbot decided to take a scenic route #off the track, proving once and for all that even machines can have "off #days." 😂 But fear not! #PTP is here to save the day with enough acronyms to make your head spin faster than a runaway #train. 🚀🔤
https://www.pentestpartners.com/security-blog/eurostar-ai-vulnerability-when-a-chatbot-goes-off-the-rails/ #Eurostar #humor #technology #machinelearning #HackerNews #ngated

Nur die Richtigkeit der Zeit bringt die Richtigkeit der Realität. Für eine Annäherung dessen bin ich immer zu haben.

Auf dem #39c3 wurde #PTP zur Synchronisation der Video Aufzeichnungen genutzt. #NTP mit mehreren ms Abweichung ist spürbar. Aber im Q&A Teil zweifel ich an, dass unser Gehör und Gehirn im ns Bereich arbeitet. µs Genauigkeit denke ich hier wäre richtig.

Und ab ins Rabbit Hole und zig Webseiten mit abweichender genauer Richtigkeit.

https://media.ccc.de/v/39c3-excuse-me-what-precise-time-is-it

Clock Synchronization: A rundown of different algorithms and systems for keeping computers in sync
https://arpitbhayani.me/blogs/clock-sync-nightmare/
#synchronization #via:hackernews #clocks #time #ntp #ptp #+

Clock Synchronization Is a Nightmare

#ntp #ptp #sync #time #unix

https://arpitbhayani.me/blogs/clock-sync-nightmare/

Shower rain on Pointe-à-Pitre Le Raizet airport (Guadeloupe) “TFFR 191430Z AUTO 07009KT 040V110 9999 FEW028 29/23 Q1016 TEMPO 3000 SHRA FEW015CB BKN020TCU” : See what it means on https://www.bigorre.org/aero/meteo/tffr/en #pointeapitreleraizetairport #airport #pointeapitre #guadeloupe #tffr #ptp #metar #aviation #aviationweather #avgeek vl

Nooooooo, #PTP is offline 😳

Shower rain on Pointe-à-Pitre Le Raizet airport (Guadeloupe) “TFFR 201200Z AUTO 10009KT 9999 FEW050/// ///CB 28/24 Q1015 TEMPO 12015G25KT 3000 SHRA” : See what it means on https://www.bigorre.org/aero/meteo/tffr/en #pointeapitre #guadeloupe #pointeapitreleraizetairport #tffr #ptp #metar #aviation #aviationweather #avgeek #airport vl

Pointe-à-Pitre Le Raizet International Airport - Pointe-à-Pitre, Guadeloupe

https://en.wikipedia.org/wiki/Pointe-%C3%A0-Pitre_International_Airport
https://www.openstreetmap.org/#map=13/16.265301/-61.531799

#TFFR #PTP #PointeàPitre #Guadeloupe #airport #aviation #avgeeks #GIS

🇺🇦 #NowPlaying on #BBC6Music's #LaurenLaverne

PTP:
🎵 Rubber Glove Seduction

#PTP

https://ministryband.bandcamp.com/track/rubber-glove-seduction-1989

https://open.spotify.com/track/521q7RBO7Lb9V54F7yPF6K

Pointe-à-Pitre Le Raizet International Airport - Pointe-à-Pitre, Guadeloupe

https://en.wikipedia.org/wiki/Pointe-%C3%A0-Pitre_International_Airport
https://www.openstreetmap.org/#map=13/16.265301/-61.531799

#TFFR #PTP #PointeàPitre #Guadeloupe #airport #aviation #avgeeks #GIS

Sub-millisecond time: Detailed experiments of trying to push the limits of time synchronization on Linux on commodity hardware. <1ms is easy, 20-60ns may be a practical limit
https://scottstuff.net/posts/2025/06/10/timing-conclusions/
#synchronization #linux #time #ntp #ptp #+

https://www.magmoe.com/2493985/movie/2025-08-18/ Pay money To my Painのドキュメンタリー映画”SUNRISE TO SUNSET”、”第5回SAITAMAなんとか映画祭”で特別上映！監督とプロデューサーによるトーク・ショーも開催！ #film #movie #P.T.P. #PayMoneyToMyPain #PTP #映画

https://www.wacoca.com/media/417781/ Pay money To my Painのドキュメンタリー映画”SUNRISE TO SUNSET”、”第5回SAITAMAなんとか映画祭”で特別上映！監督とプロデューサーによるトーク・ショーも開催！ #film #movie #P.T.P. #PayMoneyToMyPain #PTP #映画

Okay, it's time for the big #ntp and #ptp wrap-up post. My week-long timing project spiraled out of control and turned into a two month monster, complete with 7 (ish?) GPS timing devices, 14 different test NICs, and a dozen different test systems.

What'd I learn along the way? See https://scottstuff.net/posts/2025/06/10/timing-conclusions/ for the full list (and links to measurements and experimental results), but the top few are:

1. It's *absolutely* possible to get single-digit nanosecond time syncing with NTP between a pair of Linux systems with Chrony in a carefully-constructed test environment. Outside of a lab, 100-500 ns is probably more reasonable with NTP on a real network, and even that requires carefully selected NICs. But single-digit nanoseconds *are* possible. NTP isn't just for millisecond-scale time syncing.
2. Generally, PTP on the same hardware shows similar performance to NTP in a lab setting, with a bit less jitter. I'd expect it to scale *much* better in a real network, though. However, PTP mostly requires higher-end hardware (especially switches) and a bit more engineering work. Plus many older NICs just aren't very good at PTP (especially ConnectX-3s).
3. Intel's NICs, *especially* the E810 and to a lesser extent the i210 are very good at time accuracy. Unfortunately their X710 isn't as good, and the i226 is mixed. Mellanox is less accurate in my tests, with 200ns of skew, but still far better than Realtek and other consumer NICs.
4. GPS receivers aren't really *that* accurate. Even good receivers "wander" around 5-30 ns from second to second.
5. Antennas are critical. The cheap, flat window ones aren't a good choice for timing work. (Also, they're not actually supposed to be used in windows, they generally want a ground plane).
6. Your network probably has more paths with asymmetrical timing in it than you'd have expected. ECMP, LACP, and 2.5G/5G/10Gbase-T probably all negatively impact your ability to get extremely accurate time.

Anyway, it's been a fun journey. I had a good #time.

My overnight tests finished!

In my environment, I get the best #NTP accuracy with #Chrony when using `minpoll -2 maxpoll -2` and not applying any filtering. That is, have the client poll the NTP server 4 times per second. Anything between `minpoll -4` (16x/second) and `minpoll 0` (1x/second) should have similar offsets, but the jitter increases with fewer than 4 polls per second.

https://scottstuff.net/posts/2025/06/03/measuring-ntp-accuracy-with-an-oscilloscope-2/

Chrony has a `filter` option that applies a median filter to measurements; the manual claims that it's useful for high-update rate local servers. I don't see any consistent advantage to `filter` in my testing and larger filter values (8 or 16) consistently make everything worse.

When polling 4x/second on a carefully constructed test network, NTP on the client machine is less than 2 ns away from #PTP with 20 ns of jitter. I know that PTP on the client is 4 ns away from PTP on the server (w/ 2 ns of jitter), as measured via oscilloscope.

So, you could argue that this counts as single-digit nanosecond NTP error, although with 20 ns of jitter that's probably a bit optimistic. In any case, that's *well* into the range where cable lengths are a major factor in accuracy. It's a somewhat rigged test environment, but it's still much better than I'd have expected from NTP.