On 2010-03-12 12:35, Mark Townsley wrote:
> 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.
My experience was that while I was using 6to4 I experienced MTU and MSS
related problems, and they went away as soon as the university gave me
native connectivity. I can't explain that rationally, of course.
Brian
_______________________________________________
Softwires mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/softwires
