IP Fragmentation - Not reliable over the Internet?

Sun Sep 1 20:34:22 UTC 2013

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