Re: [Cerowrt-devel] trivial 6in4 fix(?)

[Sebastian Moeller <moeller0@gmx.de>]

Hi Dave, hi Toke,


On Jun 16, 2013, at 22:57 , Dave Taht <dave.taht@gmail.com> wrote:

> On Sun, Jun 16, 2013 at 1:55 PM, Toke Høiland-Jørgensen <toke@toke.dk> wrote:
>> Sebastian Moeller <moeller0@gmx.de> writes:
>> 
>>> As far as I can tell at least VDSL typically means VDSL2 and that
>>> probably means PTM instead of ATM. In essence this means you do not
>>> have to deal with ATMs 48 payload bytes per 53 byte cell transport
>>> inefficiencies. So all you need to deal with is per packet overhead.
>>> Then again I am sure you probably know that already. (Sidenote, as far
>>> as I understand (so not very far) using ATM for DSL connections with
>>> POTS service in the lower frequency range never made much sense at
>>> all, the 5 byte ATM header typically was constant and by that just
>>> ballast and the 48 byte quantization on the last mile never came with
>>> any benefits, but I digress)
>> 
>> Right, thanks. So that means the overhead is constant per (ethernet)
>> package?
> 
> So what's the MTU on VSDL2? Is PPPOE used?

	Easy to figure out empirically by hand, by finding the largest ping packet size that still passes without fragmentation (see http://www.debian.org/doc/manuals/debian-reference/ch05.en.html#_finding_optimal_mtu)

Best
	Sebastian

> 
>> -Toke
> 
> 
> 
> -- 
> Dave Täht
> 
> Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html