[email protected] <[email protected]> wrote: > On 28 Jan 2013 09:57:00 GMT, Rob <[email protected]> wrote: > >>There will be the extra complication that a UMTS connection goes into >>a "sleep mode" when there is little or no traffic. To "wake it up" >>you need to send about 4 packets/second for some time. This is a >>very typical pattern on a UMTS connection: >> >>ping -i1 172.31.32.18 >>PING (172.31.32.18) 56(84) bytes of data. >>64 bytes from (172.31.32.18): icmp_seq=1 ttl=127 time=461 ms >>64 bytes from (172.31.32.18): icmp_seq=2 ttl=127 time=377 ms >>64 bytes from (172.31.32.18): icmp_seq=3 ttl=127 time=390 ms > ........ >>64 bytes from (172.31.32.18): icmp_seq=9 ttl=127 time=246 ms >>64 bytes from (172.31.32.18): icmp_seq=10 ttl=127 time=144 ms >>64 bytes from (172.31.32.18): icmp_seq=11 ttl=127 time=50.8 ms >>64 bytes from (172.31.32.18): icmp_seq=12 ttl=127 time=52.2 ms >>64 bytes from (172.31.32.18): icmp_seq=13 ttl=127 time=102 ms >>64 bytes from (172.31.32.18): icmp_seq=14 ttl=127 time=50.4 ms >>64 bytes from (172.31.32.18): icmp_seq=15 ttl=127 time=51.4 ms >>64 bytes from (172.31.32.18): icmp_seq=16 ttl=127 time=52.4 ms >>64 bytes from (172.31.32.18): icmp_seq=17 ttl=127 time=47.6 ms >>64 bytes from (172.31.32.18): icmp_seq=18 ttl=127 time=50.1 ms >>64 bytes from (172.31.32.18): icmp_seq=19 ttl=127 time=51.4 ms >>64 bytes from (172.31.32.18): icmp_seq=20 ttl=127 time=47.4 ms >> >>As you can see, totally unsuitable for accurate time calibration. > > Would I likely get better results if I advised my users to connect to > broadband wi-fi if possible and I use that instead of 3G data?
WiFi has the same problem on a slightly smaller scale. With WiFi the pingtime jitters by 50 ms or so. _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
