Look, if IPv6 had a 32-bit checksum, it would increase their header by yet
another 4 bytes. To a monster of 44 bytes.
This is a tradeoff - add those 4 bytes or let upper layer cover that one
for you...
And assume what-if IPFF has those 4 bytes covered. Should it also cover
"Hops" aka TTL, or not? Should it also cover data or not ?
And this will not prevent device mangling (moving to NAT devices this
time), instead of Ethernet switches.
On Dec 15, 2015 3:26 PM, <lloyd(_dot_)wood(_at_)yahoo(_dot_)co(_dot_)uk> wrote:
Stewart,
we've recently had much discussion of this in tsvwg. (And
Fletcher isn't that good...)
My working theory with hindsight is that, in many ways,
IPv6 embodies the worst of all possible choices.
Lloyd Wood lloyd(_dot_)wood(_at_)yahoo(_dot_)co(_dot_)uk
http://about.me/lloydwood
------------------------------
*From:* Stewart Bryant <stbryant(_at_)cisco(_dot_)com>
*To:* lloyd(_dot_)wood(_at_)yahoo(_dot_)co(_dot_)uk; Christopher Morrow
<morrowc(_dot_)lists(_at_)gmail(_dot_)com>;
Alexey Eromenko <al4321(_at_)gmail(_dot_)com>
*Cc:* ietf <ietf(_at_)ietf(_dot_)org>; Jared Mauch
<jared(_at_)puck(_dot_)nether(_dot_)net>
*Sent:* Tuesday, 15 December 2015, 21:55
*Subject:* Re: Checksum at IP layer - is it even needed ?
Lloyd
If that is a significant risk, then why did IPv6 not move
to a better protection when it was changing the other things
in the nw/xport interface? After all there were much
better c/s - such as Fletcher - that were well known
at the time?
Stewart
On 15/12/2015 00:32, lloyd(_dot_)wood(_at_)yahoo(_dot_)co(_dot_)uk wrote:
If the content is not understood by anyone except the intended endpoint
the occasional misdelivery is surely of no consequence.
There's still a risk of port pollution (IPv4) or destination pollution
(IPv6)
from misdeliveries without checksums.
not understood != not handled and pushed up the stack.
Lloyd Wood lloyd(_dot_)wood(_at_)yahoo(_dot_)co(_dot_)uk
http://about.me/lloydwood
------------------------------
*From:* Stewart Bryant <stbryant(_at_)cisco(_dot_)com>
<stbryant(_at_)cisco(_dot_)com>
*To:* Christopher Morrow <morrowc(_dot_)lists(_at_)gmail(_dot_)com>
<morrowc(_dot_)lists(_at_)gmail(_dot_)com>; Alexey Eromenko
<al4321(_at_)gmail(_dot_)com>
<al4321(_at_)gmail(_dot_)com>
*Cc:* ietf <ietf(_at_)ietf(_dot_)org> <ietf(_at_)ietf(_dot_)org>; Jared Mauch
<jared(_at_)puck(_dot_)nether(_dot_)net>
<jared(_at_)puck(_dot_)nether(_dot_)net>
*Sent:* Tuesday, 15 December 2015, 10:04
*Subject:* Re: Checksum at IP layer - is it even needed ?
On 14/12/2015 21:55, Christopher Morrow wrote:
I suppose: "Why are we trying to solve this in tcp/udp? why not solve
this at the application layer with TLS?" .
Yes, I was wondering about this.
If the content is not understood by anyone except the intended endpoint
the occasional misdelivery is surely of no consequence.
Stewart
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