<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Feb 5, 2019, at 4:37 AM, Dave Taht <<a href="mailto:dave.taht@gmail.com" class="">dave.taht@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">Thank you mikael and jake, matt and matthew and richard! (and jon, and<br class="">dev for trying)<br class=""></div></div></blockquote><div><br class=""></div><div>+1</div><br class=""><blockquote type="cite" class=""><div class=""><div class="">and here's a puzzler for you! Both boxes are running ntp yet one box<br class="">was still *30* seconds off.<br class=""></div></div></blockquote><div><br class=""></div><div>I haven’t explored this fully but I find it works best when ntp is configured in an identical way across servers, either all running systemd-timesyncd, or ntpd, or chronyd, and to the same server pool. When that’s the case, I often see it works within a few milliseconds.</div><div><br class=""></div><div>For me, it looks like clocks are currently about 10ms off to london and 75ms off to singapore. I’m using systemd-timesyncd with the default Debian servers- "<a href="http://0.debian.pool.ntp.org" class="">0.debian.pool.ntp.org</a> <a href="http://1.debian.pool.ntp.org" class="">1.debian.pool.ntp.org</a> <a href="http://2.debian.pool.ntp.org" class="">2.debian.pool.ntp.org</a> <a href="http://3.debian.pool.ntp.org" class="">3.debian.pool.ntp.org</a>”.</div><div><br class=""></div><blockquote type="cite" class=""><div class=""><div class="">irtt 1ms between california and germany has a mindboggling amount of<br class="">loss... in america... ahh... tools…</div></div></blockquote><div><br class=""></div><div>Curiously, I see less loss at 1ms to singapore than london, london’s loss comes from the downstream, and I wasn’t seeing it four days ago. The upstream loss is my NLOS uplink as I get it straight to my next hop, which also has an irtt server.</div><div><br class=""></div><div><div class="">Next hop router:</div><div class=""><div class=""> packets sent/received: 4999/4864 (2.70% loss)</div><div class=""> server packets received: 4864/4999 (2.70%/0.00% loss up/down)</div></div></div><div><br class=""></div><div>London:</div><div><div> packets sent/received: 5000/4124 (17.52% loss)</div><div> server packets received: 4817/5000 (3.66%/14.39% loss up/down)</div><div class=""><br class=""></div><div class="">Singapore:</div><div class=""><div class=""> packets sent/received: 5000/4830 (3.40% loss)</div><div class=""> server packets received: 4830/5000 (3.40%/0.00% loss up/down)</div></div><div class=""><br class=""></div><div class="">Also curiously, RTT to london has increased for some reason, mainly with increased receive delay, but this could easily be from our peering provider, which we hope to switch soon for other reasons.</div><div class=""><br class=""></div><div class=""><font face="Monaco" class="">Feb. 1, 2019</font></div><div class=""><font face="Monaco" class="">------------</font></div><div class=""><br class=""></div><div class=""><div class=""><font face="Monaco" class="">$ irtt client -q -i 10ms -d 1s <a href="http://flent-london.bufferbloat.net" class="">flent-london.bufferbloat.net</a></font></div><div class=""><font face="Monaco" class="">[Connecting] connecting to <a href="http://flent-london.bufferbloat.net" class="">flent-london.bufferbloat.net</a></font></div><div class=""><font face="Monaco" class="">[176.58.107.8:2112] [Connected] connection established</font></div><div class=""><font face="Monaco" class="">[176.58.107.8:2112] [WaitForPackets] waiting 135ms for final packets</font></div><div class=""><font face="Monaco" class=""><br class=""></font></div><div class=""><font face="Monaco" class=""> Min Mean Median Max Stddev</font></div><div class=""><font face="Monaco" class=""> --- ---- ------ --- ------</font></div><div class=""><font face="Monaco" class=""> RTT 31.08ms 37.09ms 37.04ms 44.98ms 2.75ms</font></div><div class=""><font face="Monaco" class=""> send delay 16.02ms 21.55ms 21.39ms 29.51ms 2.67ms</font></div><div class=""><font face="Monaco" class=""> receive delay 14.3ms 15.54ms 15.61ms 17.2ms 470µs</font></div><div class=""><font face="Monaco" class=""> </font></div><div class=""><font face="Monaco" class=""> IPDV (jitter) 49.5µs 3.27ms 2.45ms 10.85ms 2.88ms</font></div><div class=""><font face="Monaco" class=""> send IPDV 63.4µs 3.16ms 2.22ms 10.79ms 2.84ms</font></div><div class=""><font face="Monaco" class=""> receive IPDV 903ns 400µs 203µs 2.82ms 506µs</font></div><div class=""><font face="Monaco" class=""> </font></div><div class=""><font face="Monaco" class=""> send call time 21.3µs 79.1µs 146µs 28.9µs</font></div><div class=""><font face="Monaco" class=""> timer error 1.84µs 721µs 2.22ms 501µs</font></div><div class=""><font face="Monaco" class=""> server proc. time 1.29µs 31.4µs 2.23ms 222µs</font></div><div class=""><font face="Monaco" class=""><br class=""></font></div><div class=""><font face="Monaco" class=""> duration: 1.13s (wait 135ms)</font></div><div class=""><font face="Monaco" class=""> packets sent/received: 100/100 (0.00% loss)</font></div><div class=""><font face="Monaco" class=""> server packets received: 100/100 (0.00%/0.00% loss up/down)</font></div><div class=""><font face="Monaco" class=""> bytes sent/received: 6000/6000</font></div><div class=""><font face="Monaco" class=""> send/receive rate: 48.5 Kbps / 48.8 Kbps</font></div><div class=""><font face="Monaco" class=""> packet length: 60 bytes</font></div><div class=""><font face="Monaco" class=""> timer stats: 0/100 (0.00%) missed, 7.21% error</font></div></div><div class=""><font face="Monaco" class=""><br class=""></font></div><div class=""><span style="font-family: Monaco;" class="">Feb. 5, 2019</span></div><div class=""><div class=""><font face="Monaco" class="">------------</font></div></div><div class=""><br class=""></div><div class=""><div class=""><div class=""><font face="Monaco" class="">$ irtt client -q -i 10ms -d 1s <a href="http://flent-london.bufferbloat.net" class="">flent-london.bufferbloat.net</a></font></div><div class=""><font face="Monaco" class="">[Connecting] connecting to <a href="http://flent-london.bufferbloat.net" class="">flent-london.bufferbloat.net</a></font></div><div class=""><font face="Monaco" class="">[176.58.107.8:2112] [Connected] connection established</font></div><div class=""><font face="Monaco" class="">[176.58.107.8:2112] [WaitForPackets] waiting 176.8ms for final packets</font></div><div class=""><font face="Monaco" class=""><br class=""></font></div><div class=""><font face="Monaco" class=""> Min Mean Median Max Stddev</font></div><div class=""><font face="Monaco" class=""> --- ---- ------ --- ------</font></div><div class=""><font face="Monaco" class=""> RTT 53.38ms 54.59ms 54.38ms 58.93ms 1.05ms</font></div><div class=""><font face="Monaco" class=""> send delay 16.81ms 18.07ms 17.87ms 22.17ms 998µs</font></div><div class=""><font face="Monaco" class=""> receive delay 35.72ms 36.52ms 36.5ms 38.07ms 333µs</font></div><div class=""><font face="Monaco" class=""> </font></div><div class=""><font face="Monaco" class=""> IPDV (jitter) 47.1µs 960µs 370µs 4.69ms 1.03ms</font></div><div class=""><font face="Monaco" class=""> send IPDV 13.4µs 974µs 646µs 4.69ms 1.04ms</font></div><div class=""><font face="Monaco" class=""> receive IPDV 5.05µs 379µs 287µs 1.51ms 322µs</font></div><div class=""><font face="Monaco" class=""> </font></div><div class=""><font face="Monaco" class=""> send call time 32.5µs 35.5µs 61µs 3.65µs</font></div><div class=""><font face="Monaco" class=""> timer error 90ns 15.1µs 190µs 25.5µs</font></div><div class=""><font face="Monaco" class=""> server proc. time 7.47µs 13.4µs 191µs 20.6µs</font></div><div class=""><font face="Monaco" class=""><br class=""></font></div><div class=""><font face="Monaco" class=""> duration: 1.17s (wait 176.8ms)</font></div><div class=""><font face="Monaco" class=""> packets sent/received: 99/77 (22.22% loss)</font></div><div class=""><font face="Monaco" class=""> server packets received: 99/99 (0.00%/22.22% loss up/down)</font></div><div class=""><font face="Monaco" class=""> bytes sent/received: 5940/4620</font></div><div class=""><font face="Monaco" class=""> send/receive rate: 48.0 Kbps / 37.3 Kbps</font></div><div class=""><font face="Monaco" class=""> packet length: 60 bytes</font></div><div class=""><font face="Monaco" class=""> timer stats: 1/100 (1.00%) missed, 0.15% error</font></div></div></div><div class=""><br class=""></div></div></div></body></html>