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Re: [RRG] Re: [RAM] Tunneling overheads and fragmentation
On 2007-09-14 09:10, Iljitsch van Beijnum wrote:
On Sep 13, 2007, at 19:23 , Dino Farinacci wrote:
I just re-read RFC 2460 section 5. Admittedly things are less
clear for IPv4, but it seems clear that IPv6 senders should not
exceed 1280 bytes (pre-encapsulation) unless they have succeeded
in discovering a larger path MTU.
Nice to hear some good news for a change. ;-)
Back to our regularly scheduled not-so-good news: there is of course the
paradox that we don't get to send large packets until we know we can,
but the only way to find out the supported packet size is by sending
large packets.
There is that paradox, but the nice thing about the Internet is that
dropped packets don't matter architecturally (either you're using a
reliable transport, or your app knows it's using an unreliable transport).
So, even despite the issues Bill Herrin mentions, things will work out
if the stack is reasonably conformant with RFC 2460 or 791.
A stack that insists on sending more than 1280 bytes without successful
PMTUD is in trouble anyway.
Brian
Brian
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