On 3/10/10 10:24 PM, Brian E Carpenter wrote:
Mark,
Your right about 1280. However, following that logic, the IPv4 Internet
should have an MTU of no greater than 576 bytes, because blackholes are
possible with MTU's larger than that. Yet the common MTU on the IPv4
Internet is 1500.
That's true today. But my experience while travelling and staying in
random hotels towards the end of the dial-up era was that I often
had to clamp the IPv4 MTU at (say) 512 to make things actually work.
I've had experience with 6to4 of abject PMTUD failures with remote servers
trying to do 1480. So I think that Remy is correct as far as a fail safe
solution *today* goes.
And thank goodness we still don't fragment all IPv4 traffic >= 512 bytes.
Since 6RD is very much a transitional technique
before an ISP is ready to run native, I don't see this as a significant
inefficiency.
The problem in this logic is that the argument for 1280 is not about the
MTU within the confines of the 6rd deployment, but outside across the
Internet. As such, it would apply equally to native IPv6 as it would to
6rd.
- Mark
Brian
Regards
Brian Carpenter
_______________________________________________
Softwires mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/softwires
_______________________________________________
Softwires mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/softwires
