Date: Thu, 25 Nov 1999 23:06:09 +0100 From: "Niels Chr. Bank-Pedersen" <ncbp@bank-pedersen.dk> To: freebsd-questions@freebsd.org Subject: ping response times over ppp Message-ID: <19991125230609.A23253@bank-pedersen.dk>
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Hi, We are doing some testing of some new network equipment, and I've stumbled across the following: 64 bytes from 192.168.10.10: icmp_seq=9 ttl=253 time=320.412 ms 64 bytes from 192.168.10.10: icmp_seq=10 ttl=253 time=310.398 ms 64 bytes from 192.168.10.10: icmp_seq=11 ttl=253 time=290.418 ms 64 bytes from 192.168.10.10: icmp_seq=12 ttl=253 time=280.416 ms 64 bytes from 192.168.10.10: icmp_seq=13 ttl=253 time=270.430 ms 64 bytes from 192.168.10.10: icmp_seq=14 ttl=253 time=260.416 ms 64 bytes from 192.168.10.10: icmp_seq=15 ttl=253 time=240.417 ms 64 bytes from 192.168.10.10: icmp_seq=16 ttl=253 time=230.387 ms 64 bytes from 192.168.10.10: icmp_seq=17 ttl=253 time=220.378 ms 64 bytes from 192.168.10.10: icmp_seq=18 ttl=253 time=210.385 ms 64 bytes from 192.168.10.10: icmp_seq=19 ttl=253 time=210.418 ms 64 bytes from 192.168.10.10: icmp_seq=20 ttl=253 time=210.364 ms 64 bytes from 192.168.10.10: icmp_seq=21 ttl=253 time=210.370 ms 64 bytes from 192.168.10.10: icmp_seq=22 ttl=253 time=210.361 ms 64 bytes from 192.168.10.10: icmp_seq=23 ttl=253 time=210.392 ms All responsetimes equals n*10 + epsilon [ms]. I'm pretty sure we don't have any queuing involved that could influence the results, so my question is whether this is caused by timeresolution problems within either ping or ppp; or I'm just plain lucky to hit n*10 every time? :) The problem doesn't seem to influence pings across Ethernet (at least not with t<10ms): 64 bytes from 192.168.20.10: icmp_seq=0 ttl=255 time=0.998 ms 64 bytes from 192.168.20.10: icmp_seq=1 ttl=255 time=1.055 ms 64 bytes from 192.168.20.10: icmp_seq=2 ttl=255 time=1.035 ms 64 bytes from 192.168.20.10: icmp_seq=3 ttl=255 time=1.067 ms 64 bytes from 192.168.20.10: icmp_seq=4 ttl=255 time=1.025 ms 64 bytes from 192.168.20.10: icmp_seq=5 ttl=255 time=0.997 ms 64 bytes from 192.168.20.10: icmp_seq=6 ttl=255 time=1.043 ms 64 bytes from 192.168.20.10: icmp_seq=7 ttl=255 time=1.012 ms 64 bytes from 192.168.20.10: icmp_seq=8 ttl=255 time=0.996 ms 64 bytes from 192.168.20.10: icmp_seq=9 ttl=255 time=1.022 ms This is done on a $ uname -a FreeBSD test.tele.dk 3.3-STABLE FreeBSD 3.3-STABLE #0: Thu Oct 21 19:49:26 CEST 1999 root@test.tele.dk:/usr/src/sys/compile/GENERIC i386 TIA /Niels Chr. -- Niels Christian Bank-Pedersen, NCB1-RIPE. Network Manager, Tele Danmark NET, IP-section. "Hey, are any of you guys out there actually *using* RFC 2549?" To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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