Hi Mark,
Actually fragmentation works well unless you have a firewall that drops
fragments. When they are not being deliberately blocked the packets get
through and are reassembled. It is also not many operators. It is some
operators.
The words "many" and "some" don't do justice to the conversation.
https://tools.ietf.org/html/draft-ietf-v6ops-ipv6-ehs-in-real-world-02 provides
more concrete numbers from real-world observation.
Beyond that, I agree that IPv6 fragmentation works perfectly unless firewalls
are configured to make it stop working. Sadly, the number of network in which
firewalls are so configured is too large to ignore. See the draft mentioned
above.
Additionally there is zero reasons why firewalls can't open <src, dst, frag
offset != 0> when they open <src, dst, proto, src port, dst port> for reply
traffic for those that are paranoid about just letting all non-zero fragment
offset through. I just let the non-zero offset fragments through.
You might get a few extra packet through.
So, you are voicing support for Option 2a (i.e., Convince operators not to drop
fragmented packets). This will clearly take time. Do you think that we should
do anything else in the interim? Maybe 1b) Write an RFC informing developers of
UDP applications of the problem and advising them not to rely on protocol MTU >
1280.
Ron