I know I'm digging up an old thread here but I've spent some time analyzing some of the significant changes that Apple has made to the Facetime protocol, apparently with a huge focus on IP packet size to avoid fragmentation issues:
http://blog.krisk.org/2013/09/apples-new-facetime-sip-perspective.html I'm betting they've had HUGE issues with IP+UDP MTU issues over the last three years... On Sun, Sep 1, 2013 at 4:34 PM, Emile Aben <emile.a...@ripe.net> wrote: > On 31/08/2013 13:13, Randy Bush wrote: >> could you please test with ipv6? > > This is what I see for various IPv6 payloads (large ICMPv6 echo > requests) from all RIPE Atlas probes that where available at the time to > a single "known good" MTU 1500 destination: > > plen fail% nr_probes > 100 9.64 1266 > 500 9.34 1039 > 1000 9.94 1298 > 1240 9.94 1308 > 1241 11.62 1300 > 1440 12.70 890 > 1441 14.70 1306 > 1460 15.18 1304 > 1461 19.84 1290 > 1462 22.02 1294 > > plen: IPv6 payload length (ie. not including 40byte IPv6 header) > fail%: percentage of probes that didn't get any of the 5 pkts that were > sent. Note that there is a large baseline failure rate in IPv6 on RIPE > Atlas probes [1], which would explain the ~10% failure rate for the > smaller packets. > > I plan to do more analysis and start writing this up on RIPE Labs over > the next few days. > > cheers, > Emile Aben > RIPE NCC > > > [1] > https://labs.ripe.net/Members/stephane_bortzmeyer/how-many-atlas-probes-believe-they-have-ipv6-but-are-wrong > -- Kristian Kielhofner