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Re: Evolution of the IP model - ICMP and MTUs
On 18 aug 2008, at 8:45, Rémi Després wrote:
IMU,
IMU?
since it shows that, at high data rates, IPv4 fragmentation can lead
to undetected data corruption at the IP layer, it implies that
fragmentation SHOULD be discarded from an updated IPv4 service model
(the DF bit MUST be set in all packets).
What about actually FIXING the problem.
I remember that when I first read about IPv6 (many a moon ago) I
noticed that IP packets had an unfragmentable and fragmentable parts.
So I thought "excellent, they got it right, the port numbers are now
in all fragments!" Unfortunately, that wasn't the case.
However, we could come up with a new fragment header for both IPv6 and
IPv4 that DOES have all the information NATs and firewalls need in the
fragment header, as well as a larger ID field. This would of course
take significant time to get deployed, but considering that we've been
limping along with broken PTMUD for a decade and a half having a GOOD
solution may be worth the wait.