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.aben@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-beli...
-- Kristian Kielhofner